Thoracic vertebrae, vertebrae thoracicae, articulate with the ribs, so they differ in that they have costal fossa, foveae costales, connected to the heads of the ribs and located on the body of each vertebra near the base of the arch.

Since the ribs are usually articulated with two adjacent vertebrae, most of the bodies of the thoracic vertebrae have two incomplete (half) costal fossa: one at the upper edge of the vertebra, fovea costalis superior and the other on the bottom fovea costalis inferior .

The exception is the I thoracic vertebra, which on the upper edge has a full glenoid fossa for the I rib, and on the lower edge - half for the II rib. Further, the X vertebra has only one upper half-pit for the X rib, while on the XI and XII vertebrae there is one complete fossa for articulation with the corresponding ribs. Thus, the named vertebrae (I, X, XI and XII) are very easy to distinguish from others.

Body thoracic vertebrae correspondingly to the greater load falling on them, there are more bodies of the cervical vertebrae. The articular processes are frontal. The transverse processes are directed to the sides and back. On their front side there is a small articular surface, fovea costdlis processus transversus , - the place of articulation with the tubercle of the ribs. On the transverse processes of the last two vertebrae (XI and XII), these articular surfaces are absent.

Spinous processes of the thoracic vertebrae long and strongly inclined downward, as a result of which they overlap each other like tiles, mainly in the middle part of the thoracic spine.

Lumbar vertebrae, vertebrae lumbales, They are distinguished by the massiveness of the bodies, respectively, even greater than that of the overlying spinal column, the load. The spinous processes are directed straight back, the articular processes are sagittal.

Transverse process for the most part, it is a rudimentary rib, completely merged with a real transverse process and partly preserved as a small process behind its base, incorrectly called additional, processus accessorius(accessorius - additional, joining) (fig. 17).

Spine sections

Figure № 7. Spine sections

Let's continue our tour of the entertaining anatomy of the spine. So, vertebral column is part of the axial skeleton. This structure, unique in its support and shock-absorbing functions, not only connects the skull, ribs, pelvic girdle, but also serves as a receptacle for the spinal cord. The human spine consists of 32-34 vertebrae. Why are such approximate figures given? Because, as you remember, we are talking about the anatomy of the "average" person. But in fact, the spine, like any other living structure, may have its own small quantitative (and qualitative) deviations, that is, its own individual structural features.

In this main part of the axial skeleton of a person, the cervical, thoracic, lumbar, sacral and coccygeal regions are distinguished. Let us consider in more detail these departments and the most typical number of their vertebrae.

The cervical region is the most mobile. It contains 7 vertebrae. Latin name vertebrae cervicales- cervical vertebrae ( vertebra- vertebra; cervix- neck). In medical documents, the vertebrae of this department are marked with the Latin letter "C" - an abbreviation for the word cervicales, and the index assigned to the letter, for example C1, C2, C3, etc., means the number of the vertebra - the first cervical vertebra (C1), the second cervical vertebra (C2), etc.

These vertebrae have less load in comparison with the underlying parts of the spinal column, and therefore they look more "miniature". Particularly noteworthy are the first two cervical vertebrae, which differ significantly from the others (they are also called atypical vertebrae). Although they are small in size, they are the most responsible workers who are responsible for the movable joint with the skull. Almost like people who are close to the very top of the government and are responsible for ... Well, let's not talk about that.

Therefore, I and II cervical vertebrae have not only a special shape, differing in their structure from other vertebrae, but also personal names: atlas and epistrophy.

Magnetic resonance imaging (MPT) # 1 shows the cervical spine, in a relatively normal state.

The cervical spine should have a normally expressed physiological lordosis, there should be no hypolordosis or hyperlordosis, as well as kyphotic deformities.

Spinal cord width: sagittal> 6-7 mm

1. Sagittal size of the spinal canal at the level:
C1 ≥ 21 mm
C2 ≥ 20 mm
C3 ≥ 17 mm
C4-C5 = 14mm

2. Height of intervertebral spaces:
C2< С3 < С4 < С5 < С6 ≥ С7

3. Width of the spinal canal: transverse diameter at the level of the legs:> 20-21 mm

Figure № 8. The first cervical vertebra - atlas. View from above

1 - vertebral foramen;
2 - posterior tubercle;
3 - back arc;
4 - groove of the vertebral artery;
5 - opening of the transverse process;
6 - upper glenoid fossa;
7 - transverse process;
8 - lateral mass;
9 - tooth fossa;
10 - anterior tubercle;
11 - anterior arch.

Everyone probably heard the name Atlas in childhood from the cycle of ancient legends about the gods of Olympus. True, the legends about the latter remind me more of what the Roman poet Horace once said: Decipimur specie recti, which means "We are deceived by the appearance of the right." So, according to ancient Greek mythology, there was such a titan Atlas (brother of Prometheus), who, as punishment for participating in the struggle of the titans against the Olympian gods, held the firmament on his shoulders by order of Zeus. In honor of Atlanta (Greek. atlas) and the first cervical vertebra was named. It is curious that this vertebra is devoid of spinous and articular processes, does not even have a body and notches. It consists of two arches connected by lateral bony thickenings. Everything is as it happens with people in the vertical of power, they say, among the blind and crooked - the king. With its superior glenoid fossa, the atlas attaches to the condyles (bony protrusions that are part of the articulation) of the occipital bone. The latter, so to speak, limit the degree of freedom (mobility) of the Atlantean, so that this vertebra knows its place and does not go beyond what is permitted.

Picture No. 9. Second cervical vertebra - epistrophy (axial - axis). Back and top view

1 - the tooth of the axial vertebra;
2 - posterior articular surface;
3 - upper articular surface;
4 - vertebral body;
5 - transverse process;
6 - opening of the transverse process;
7 - lower articular process;
8 - spinous process;
9 - arch of the vertebra

The second cervical vertebra is an epistrophy. So he was named by Andreas Vesalius - a doctor, the founder of scientific anatomy, who lived in the Renaissance. Greek word epistrepho means turning, turning. The Latin name for the second cervical vertebra is axis(axis), that is, axial. This vertebra is no less important than the atlas, if we speak with humor, it is still that "quirky goose". It has a bony outgrowth - a process similar to a tooth (called a dentate process), around which the atlas rotates along with the skull articulating with it. If we draw parallels with human life, then the second cervical vertebra is similar to those people who hold on to power due to incriminating evidence on their bosses. It is not for nothing that the people say, "this man is sharpening his grudge against the bosses." This is how he is, the epistrophy, small, inconspicuous, and holds his whole head. However, no matter how these vertebrae are called, both of them constitute a unique mechanism, thanks to which a person can make various movements of his head, make the same turns, tilts, including hitting his forehead, when he submits his petition to the authorities.

Picture No. 10. Typical cervical vertebra (C3-C7).
View from above
1 - vertebral foramen;
2 - arch of the vertebra;
3 - spinous process;
4 - upper articular process;
5 - lower articular process;
6 - transverse process;
7 - posterior tubercle of the transverse process;
8 - anterior tubercle;
9 - vertebral body;
10 - transverse hole

In general, the cervical spine is a "special department" of the vertebral employees, who are also responsible for the safety of the head. Due to its unique design and work, the cervical spine provides an opportunity for the head to follow, to keep under control (visual, of course) a fairly extensive part of the spatial horizons with the least mobility of the "working" organism as a whole. In addition, the transverse processes of all cervical vertebrae have special openings that are absent in other vertebrae. Together, these openings, with the natural position of the cervical vertebrae, form a bony canal in which the vertebral artery passes, which supplies the brain with blood.

Photo № 1. Model of the human cervical spine, which clearly shows how the vertebral artery passes through the holes in the transverse processes, thus forming a bony canal for the vertebral artery.

Is in cervical spine spine and their "operative" - ​​articular processes that take part in the formation of facet joints. And since the articular surfaces on these processes are located closer to the horizontal plane, then in aggregate this significantly expands the capabilities of the cervical spine, provides more effective head mobility, and allows you to achieve a greater angle of twisting. However, the latter just became vulnerability for the cervical spine, given the low strength of the cervical vertebrae, their weight and degree of mobility. As the saying goes, even the “special department” has its own “Achilles heel”.

Find out exactly where the limits of your "special department" end, you can on the seventh cervical vertebra. The fact is that the length of the spinous processes (by the way, their ends are bifurcated, except for VII) increases from II to VII vertebra. The spinous process of the seventh cervical vertebra is the longest and, moreover, thickened at the end. It is a very noticeable anatomical landmark: when the head is tilted on the back of the neck, the tip of the most protruding spinous process is well felt. By the way, this vertebra is called that in Latin. vertebra prominens- protruding vertebra. This is the very legendary "seven", thanks to which you can count your vertebrae with diagnostic accuracy.

The thoracic spine consists of 12 vertebrae. Latin name vertebrae thoracicae- thoracic vertebrae. Latin word thorax- chest - derived from the Greek word thoraks- breast. In medical documents, the thoracic vertebrae are referred to as "Th" or "T". The height of the bodies of these vertebrae gradually increases from I to XII vertebra. The spinous processes are superimposed on each other in a tile-like manner, covering the arches of the underlying vertebrae.

MRI # 2 shows the thoracic region in a “normal” state.

The thoracic region should have a normal degree of kyphosis (the Stagnara kyphosis angle is formed by a line parallel to the T3 endplates and T11 = 25 °).

The vertebral canal at the thoracic level has a rounded shape, which makes the epidural space narrow almost along the entire circumference of the dural sac (0.2-0.4 cm), and it is narrowest in the area between T6 and T9.

Sagittal size: T1-T11 = 13-14 mm, T12 = 15mm.
Cross diameter:> 20-21 mm.
The height of the intervertebral discs: the smallest at the T1 level, at the T6-T11 level approximately 4-5 mm, the highest at the T11-T12 level.

Figure 11. Thoracic vertebra. View from above
1 - arch of the vertebra;
2 - spinous process;
3 - transverse process;
4 - costal fossa of the transverse process;
5 - vertebral foramen;
6 - upper articular process;
7 - superior costal fossa;
8 - vertebral body

Also, a characteristic feature for most of the thoracic vertebrae is the presence on the lateral surfaces of the bodies of the upper and lower costal fossa for articulation with the heads of the ribs, as well as the presence of a costal fossa on the transverse processes to connect with the tubercle of the rib. Due to the specifics of its design, the small height of the intervertebral discs, this section is certainly not as mobile as the cervical section. However, it is intended for other purposes. The vertebrae of the thoracic region in conjunction with the thoracic ribs, the sternum form the bony base of the upper body - the chest, which is a support for shoulder girdle, a repository of vital organs. It allows you to use the intercostal muscles during respiratory movements. The connection of the thoracic vertebrae with the ribs gives this part of the spine greater rigidity due to the rib cage of the chest. So these vertebrae can be figuratively compared with people who work harmoniously and effectively in one big team, clearly performing their functions and responsibilities.

MRI # 3 shows the lumbar spine. (This "control" image shows the residual effects of the degenerative-dystrophic process in the L5-S1 segment after the elimination by the method of vertebrorevitology of the sequestered herniated disc.)

In the lumbar region, the shape of the spinal canal, created by the body and vertebral arches, is variable, but more often it is pentagonal. Normally, the spinal canal in the lumbosacral region is narrowed in the anteroposterior diameter at the level of L3 and L4 vertebrae. Its diameter increases caudally, and the cross-section of the canal acquires a nearly triangular shape at the L5-S1 level. In women, the canal tends to widen in the lower sacral region. The sagittal diameter decreases significantly from L1 to L3, is almost unchanged from L3 to L4, and increases from L4 to L5.

Normally, the anteroposterior diameter of the spinal canal is on average 21 mm (15-25 mm).

There is a simple and convenient formula for determining the width of the spinal canal:

normal sagittal size is not less than 15 mm;
11-15 mm - relative stenosis;
less than 10 mm - absolute stenosis. A decrease in this ratio indicates a narrowing of the channel.

The height of the lumbar intervertebral discs is 8-12 mm, increases from L1 to L4-L5, usually decreases at the L4-S1 level.

Lumbar the spine is made up of 5 largest vertebrae, which have massive, bean-shaped vertebral bodies, strong processes. The height and width of the vertebral bodies gradually increase from the first to the fifth vertebra. Latin name vertebrae lumbales- lumbar vertebrae, lat. lumbalis- lower back. Accordingly, the following are designated: the first lumbar vertebra - L1, the second lumbar vertebra - L2, and so on. The movable lumbar spine connects the sedentary thoracic region with the immobile sacrum. These are the real "hard workers" who, not only are experiencing significant pressure from the upper body, but also in life are exposed to serious additional load, which was partially discussed in the previous chapter.

Figure № 12. Lumbar vertebra. View from above
1 - vertebral foramen;
2 - spinous process;
3 - arch of the vertebra;
4 - lower articular process;
5 - upper articular process;
6 - mastoid process;
7 - transverse process;
8 - the leg of the vertebral arch;
9 - vertebral body.

The lumbar vertebrae can be figuratively compared only with heavy peasants. In the old days in Russia (in the 15th century) there were such men who worked from dawn to dawn, and even pulled full tax. Tax in the old days meant a different tax, more precisely state taxes, as well as the fulfillment of state duties. The state taxed the peasant laborer from all sides. In addition, he had to pull this tax not only for himself, but also for his family, at the rate of two souls for one tax. It's just a real lumbar vertebra with its loads. So after all, even according to the old laws, this peasant remained burdensome from marriage until he was 60 years old - "until the peasant, according to his years and health, was considered burdensome." And after that he either switched to "semi-heavy", or "a quarter of the tax", or completely shifted. Directly common truth regarding the lumbar vertebrae and the spine as a whole in a negligent owner! As long as the spine is young, it is full of health and works tirelessly, the owner mercilessly exploits it. And as degenerative-dystrophic processes began in the spine, osteochondrosis began to develop, so it already starts to work half-heartedly, and then you look at a quarter of the strength. Then it wears out altogether. And the most interesting thing is that most often it is the lumbar region that wears out. This is the life of the spine of the owner, who wastefully and carelessly spent his health: as they used to say in the old days, “and you had to marry at the age of eighteen in order to sit down on tax”.

Figure № 13. Sacrum and tailbone. Front view.

Sacrum:
1 - the base of the sacrum;
2 - upper articular process;
3 - lateral part;
4 - anterior sacral foramen;
5 - transverse lines;
6 - the top of the sacrum;
7 - sacral vertebrae.

Coccyx:
8 - coccygeal vertebrae;
9 - lateral outgrowths (rudiments of transverse processes);
10 - coccygeal horns (rudiments of the upper articular processes).

The sacral spine also consists of 5 vertebrae, fused into one bone. Anatomical name in Latin: os sacrum- sacral bone, vertebrae sacrales- sacral vertebrae, which are designated respectively S1, S2, etc. It is curious that the word sacrum used in Latin to denote mystery (Fuck. The word "sacer" means "sacred". Used because this particular bone was used in sacrifices. And they used it because because of its structure it is difficult to gnaw. All other bones were safely cleaned up by the priests http: // www. etymonline.com/index.php?term=sacrum - HB) ... This bone deserves such a name, given its structure, functions and the heavy loads that it can withstand due to the vertical position of the body. It is interesting that in children and adolescents, the sacral vertebrae are located separately, only by the age of 17-25 they are tightly fused together with the formation of a kind of monolith - a large triangular structure. This wedge-shaped structure, with the base facing up and the top facing down, is called the sacrum. The base of the sacrum (SI) has superior articular processes articulating with the inferior articular processes of the fifth lumbar vertebra (LV). Also, the base has a ledge directed forward - a cape. From the side of the apex, the sacrum connects to the first coccygeal vertebra (CO1).

In general, it should be noted that the relief of the sacrum is very interesting and in many ways mysterious. Its anterior surface is concave, has transverse lines (where the vertebral bodies meet), four pairs of pelvic sacral foramina through which the spinal nerves exit. The posterior surface is convex. It has, respectively, four pairs of dorsal sacral foramen, five longitudinal ridges formed by fusion of spinous, articular, transverse processes of the sacral vertebrae. On the lateral parts of the sacrum, there are so-called articular ear-shaped surfaces intended for articulation with the pelvic bones. Behind these articular surfaces is the sacral tuberosity, to which the ligaments are attached.

The sacral canal passes inside the sacrum, which is a continuation of the spinal canal. In the lower part, it ends with a sacral fissure, on each side of which there is a sacral horn (a rudiment of the articular process). The sacral canal contains the terminal thread of the spinal cord, the roots of the lumbar and sacral spinal nerves, that is, nerve trunks that are very important for the body, which provide innervation to the pelvic organs and lower extremities. In men, the sacrum is longer, narrower and sharply bent towards the pelvic cavity. But in women, the sacrum bone is flat, short and wide. This anatomical structure of the female sacrum helps to form a smooth inner surface of the female pelvis, which is necessary for the safe passage of the fetus during childbirth.

With its characteristics, structural features, functions, the sacrum in a figurative comparison resembles the most ancient institution of human society: a set of close people united through the sacrament into a monolithic, strong family - the cell of society, the support of statehood. In general, such people who are close to each other, who perform not only a reproductive function and are connected by a common life, but are also united by a single responsibility, mutual help, coherence in life and relationships.

The last, smallest part of the spine is the tailbone. If we take this issue with humor, then we can figuratively say about it this way: in the family, as they say, ... not without a rudiment. The tailbone is a real rudiment (from the Latin rudimentum- the rudiment, the fundamental principle) of the caudal skeleton of animals. The anatomical name of the tailbone in Latin sounds like os coccygis- tailbone bone, vertebrae coccygeae- coccygeal vertebrae. In Latin "Coccyx" interpreted as the word "cuckoo" (this designation came from the ancient Greek language), and in principle the bone was so named, due to the resemblance to the beak of a cuckoo.

Picture No. 14. Sacrum and coccyx. Back view.

Sacrum:
1 - superior articular process;
2 - sacral canal (upper opening);
3- sacral tuberosity;
4 - ear-shaped surface;
5 - lateral sacral crest;
6 - medial sacral crest;
7 - the median sacral crest;
8 - dorsal (posterior) sacral foramen;
9 - sacral horn;
10 - sacral gap (lower opening of the sacral canal).

Coccyx:
11 - coccygeal vertebrae;
12 - lateral outgrowths;
13 - coccygeal horns.

The tailbone consists of 3-5 rudimentary vertebrae, fused into one bone. They are designated as CO1, O2, and so on. It is curious that in the early stages of development, the human embryo has a tail process, which sometimes persists even after birth. However, this is not a problem for medicine: the tail can be easily removed without consequences for the body. In an adult, the tailbone is a single sedentary structure, which is similar in shape to a pyramid, directed upward with the base, and with the top directed downward and forward. The first coccygeal vertebra has an unusual appearance. Its small body articulates with the sacrum, has lateral outgrowths (rudiments of transverse processes). And on the back surface of the body are the coccygeal horns (rudiments of the upper articular processes), which are directed up to the horns of the sacrum and are connected to them through ligaments. The rest of the coccygeal vertebrae are small and rounded. There are many nerve endings in the surrounding tissues of the coccyx. The muscles and fascia of the perineum are attached to the tailbone. In women, the coccyx is more mobile; during childbirth, the dorsal deviation of the coccyx provides the expansion of the birth canal. So this rudiment is not so useless as it seems at first glance.

Thus, we briefly examined the sections of the spinal column - this amazing design, which is optimally adapted for the vertical position of the body, works clearly and harmoniously. But this is, so to speak, a review as a whole. Now I would like to draw your attention to interesting details from the same field of osteology (the doctrine of bones), concerning the important elements of the musculoskeletal system. The human spine is a segmental organ (the word "segment" comes from the Latin word segmentum- "section"). It consists of individual vertebrae, intervertebral discs located between them, as well as ligaments and joints.

Humerus, long bone. It distinguishes between the body and two pineal glands - the upper proximal and lower distal. The body of the humerus, corpus humeri, is rounded in the upper section, and triangular in the lower one.

In the lower part of the body, the posterior surface is distinguished, the facies posterior, which is circumferentially bounded by the lateral and medial edges, margo lateralis et margo medialis; the medial anterior surface, facies anterior medialis, and the lateral anterior surface, facies anterior lateralis, separated by an inconspicuous ridge.

On the medial anterior surface body of the humerus, slightly below the middle of the body's length, there is a feeding opening, foramen nutricium, which leads to a distally directed feeding channel, canalis nutricius.

Above the feeding hole on the lateral anterior surface of the body there is a deltoid tuberosity, tuberositas deltoidea, - the place of attachment, m. deltoideus.

On the back surface of the body of the humerus, behind the deltoid tuberosity, there is a groove of the radial nerve, sulcus n. radialis. It has a spiral course and is directed from top to bottom and from the inside to the outside.

Upper, or proximal, pineal gland, extremitas superior, s. epiphysis proximalis. thickened and bears a hemispherical the head of the humerus, caput humeri, the surface of which is turned inward, upward and somewhat posteriorly. The periphery of the head is delimited from the rest of the bone by a shallow annular narrowing - an anatomical neck, collum anatomicum. Below the anatomical neck, on the antero-outer surface of the bone, there are two tubercles: outside - a large tubercle, tuberculum majus, and from the inside and slightly in front - a small tubercle, tuberculum minus.

Downward from each tubercle stretches the ridge of the same name; the crest of the greater tubercle, crista tuberculi majoris, and the crest of the lesser tubercle, crista tuberculi minoris. Heading down, the ridges reach the upper parts of the body and, together with the tubercles, limit the well-defined intertubercular sulcus, sulcus intertubercularis, in which the tendon of the long head of the biceps brachii, tendo capitis longi m, lies. bicepitis brachii.
Below the tubercles, at the border of the upper end and the body of the humerus, there is a slight narrowing - the surgical neck, collum chirurgicum, which corresponds to the area of ​​the pineal gland.

On the anterior surface of the distal epiphysis of the humerus above the block is the coronary fossa, fossa coronoidea, and above the head of the condyle of the humerus is the radial fossa, fossa radialis, on the posterior surface is the fossa of the olecranon, fossa olecrani.

Peripheral divisions of the lower end humerus end with lateral and medial epicondyles, epicondylus lateralis et medialis, from which the muscles of the forearm begin.

AXIAL SKELETON BONES - OSSA SKELETI AXIALIS

The axial skeleton, skeleton axiale, is represented by the bones of the skull, spinal column and chest. The last two sections make up the bones of the body.

BONE BODY

Bones of the trunk, ossa trunci, combine the vertebral column, columna vertebralis, and bones of the chest, ossa thoracis

Vertebral column

In the spinal column, there are cervical vertebrae, vertebrae cervicales (7), thoracic vertebrae, vertebrae thoracicae (12), lumbar vertebrae, vertebral lumbales (5), sacrum, os sacrum (5), and coccyx, os coccygis (4 or 5 vertebrae) ...

The vertebral column of an adult forms four bends in the sagittal plane, curvaturae: cervical, thoracic, lumbar (abdominal) and sacral (pelvic). In this case, the cervical and lumbar bends are convex to the front (lordosis), and the thoracic and pelvic bends - posteriorly (kyphosis).

All vertebrae are divided into two groups: the so-called true and false vertebrae. The first group includes the cervical, thoracic and lumbar vertebrae, the second - the sacral vertebrae, fused into the sacrum, and the coccygeal, fused into the coccyx.

The vertebra, vertebra (Fig. 8), has a body, an arch and processes. The vertebral body, corpus vertebrae (vertebralis), is the anterior thickened part of the vertebra. Above and below it is bounded by surfaces facing, respectively, the above- and lower-lying vertebrae, in front and on the sides - a somewhat concave surface, and behind - a flattened one.

On the vertebral body, especially on its posterior surface, there are many nutrient holes, ramina nutricia, - traces of the passage of blood vessels and nerves into the bone substance. The vertebral bodies are interconnected by intervertebral discs (cartilage) and form a very flexible column of the vertebral column, columna vertebralis (see Fig. 7).

The arch of the vertebra, arcus vertebrae (vertebralis), limits the back and sides of the vertebral foramen, foramen vertebrale; located one above the other, the holes form the spinal canal, canalis vertebralis, in which lies spinal cord... From the posterolateral edges of the vertebral body, the arc begins with a narrowed segment - this is the leg of the vertebral arch, pediculus arcus vertebrae (vertebralis), passing into the plate of the vertebral arch, lamina arcus vertebrae (vertebralis). On the upper and lower surfaces of the leg there is an upper vertebral notch, incisura vertebralis superior, and a lower vertebral notch, incisura vertebralis inferior. Bepxnaya notch of one vertebra, adjacent to the lower notch of the upper vertebra, forms an intervertebral foramen, formen intervertebrale, for the passage of the spinal nerve and blood vessels.

The processes of the vertebra, processus vertebrae, in the amount of seven, protrude on the arch of the vertebra. One of them, unpaired, is directed from the middle of the arc posteriorly - this is the spinous process, processus spinosus. The rest of the processes are paired. One pair - the upper articular processes, processus articulares superiores, is located on the side of the upper surface of the arch, the other pair - the lower articular processes, prosessus articulares inferiores, protrudes from the side of the lower surface of the arch and the third pair - transverse processes, processus transversi, departs from the side of the lateral surfaces arcs.

On the articular processes there are articular surfaces, facies articulares. With these surfaces, each overlying vertebra articulates with the underlying one.

Fig. 7. Vertebral column, columna vertebralis. A - right side view; B - front view; B - rear view.

Fig. 8. Eighth thoracic vertebra, vertebra thoracica; view from above.

Cervical vertebrae

Cervical vertebrae, ve rtebrae cervicales (Fig. 9 - 20), number 7 (C1-C7), with the exception of the first two, are characterized by small low bodies, gradually expanding towards the last, 7, vertebra. The upper surface of the body is slightly concave from right to left, and the lower one is concave from front to back. On the upper surface of the bodies of 3 - 6 cervical vertebrae, the lateral edges rise noticeably, forming a hook of the body, uncus corporis (see Fig. 14, 15).

Vertebral foramen, foramen vertebrale, wide, close to triangular in shape.

The articular processes, processu s articulares, are relatively short, oblique, their articular surfaces are flat or slightly convex.

The spinous processes, processesu s spi nosi, from 2 to 7 vertebrae gradually increase in length. Up to the 6th vertebra, inclusive, they are split at the ends and have a weakly expressed downward slope.

The transverse processes, processus tran sversi, are short and directed to the sides. A deep groove of the spinal nerve, sulcus nervi spinal is (see Fig. 15), runs along the upper surface of each process, a trace of the adhesion of the cervical nerve. It separates the anterior and posterior tubercles, tuberculum anterius et tuberculum posterius, located at the end of the transverse process.

On the 6th cervical vertebra, the anterior tubercle is especially developed. The common carotid artery passes in front of and close to it, as well. Carotis communis, which is pressed against this tubercle during bleeding; hence, the tubercle was called sleepy, tubercu lu m caro ticu m (see Fig. 15).

In the cervical vertebrae, the transverse process is formed by two processes. The anterior one is the rudiment of the rib, the posterior one is the actual transverse process. Both processes together limit the opening of the transverse process, f oramen processu s tran sv ersi, through which the vertebral artery, vein and their accompanying sympathetic plexus pass, in connection with which this opening is also called the vertebral arterial (foramen vertebraarteriale).

C1 - atlant, atl as, C2 - axial vertebra, axis, and C7 - protruding vertebra, ve rt ebra prominens differ from the general type of cervical vertebrae.

The first (1) cervical vertebra, atlas, atlas (see Fig. 9.10.13), does not have a body and spinous process, but is a ring formed from two arcs - anterior and posterior, arcus anterior et arcus posterior, connected between themselves two more developed parts - lateral masses, massae laterales. Each of them has an oval concave upper articular surface on top, facies articularis superior, - a place of articulation with the occipital bone, and from below an almost flat lower articular surface, facies articularis inferior, articulating with 2 cervical vertebra.

Fig. 9. First cervical vertebra, atlas, atlas; view from above

Fig. 10. First cervical vertebra, atlas, atlas; bottom view

The anterior arch, arcus anteri or, has on its front surface an anterior tubercle, tuberculum an teriu s, on the posterior one, a small articular platform - a fossa of the tooth, fovea den tis, articulating with the tooth of the 2nd cervical vertebra.

The posterior arch, arcus posterior, at the site of the spinous process has a posterior tubercle, tuberculum posteri us. On the upper surface of the posterior arch, there is a groove of the vertebral artery, sulcu s arteri ae vertebralis, which sometimes turns into a canal.

The second (2) cervical vertebra, or axial vertebra, axis (see Fig. 11 - 13), has a tooth directed upward from the vertebral body, den s, which ends with an apex, arech. Around this tooth, like around an axis, the atlas rotates together with the skull.

Fig. 11. Second cervical, axial, vertebra, axis; front view

Fig. 12. Second cervical, axial, vertebra, axis; left view

Fig. 13. First and second cervical vertebrae; rear and right view

Fig. 16. Fourth cervical vertebra cervicalis; bottom view

There is an anterior articular surface on the front surface of the tooth, facies art i c u laris a n ter i or, with which the fossa of the atlas tooth is articulated, on the posterior surface - the posterior articular surface, facies artic u laris po st er i or, to which the transverse ligament of the atlas is adjacent, lig. tra n svers u m atla n tis. On the transverse processes, the anterior and posterior tubercles and the groove of the spinal nerve are absent.

Fig. 14. Sixth cervical vertebra, vertebra cervicalis; front view

Fig. 15. Sixth cervical vertebra, vertebra cervicalis; view from above

Fig. 17. 6th cervical vertebra, protruding; vertebra cervicalis; right view

Fig. 18. Seventh cervical, vertebra, vertebra prominens; right view

The seventh cervical vertebra, or protruding vertebra, vertebra prominens (C7)
(see Fig. 18), is distinguished by a long and undifferentiated spinous process, which is easily palpable through the skin, in this regard, the vertebra was named protruding. In addition, it has long transverse processes; its transverse holes are very small, sometimes they may be absent.
On the lower edge of the lateral surface of the body, there is often a facet, or costal fossa, fovea costalis, a trace of articulation with the head of 1 rib.

Fig. 19. The cervical part of the spinal column; front view (radiograph)

1 - the body of the 5th cervical vertebra;
2 - articular process;
3 - spinous process;

Fig. 20. The cervical part of the spinal column; side view (radiograph)

1 - 1st cervical vertebra; 2- 2nd cervical vertebra;
3 - transverse process; 4- spinous process;
5 - articular process; 6- vertebral body;

Thoracic vertebrae

The thoracic vertebrae, vertebrae thoracicae (Fig. 21-23; see Fig. 7, 8), number 12 (Th1-Th12), much higher and thicker than the cervical; the size of their bodies gradually increases towards the lumbar vertebrae.

Fig. 21 Eighth thoracic vertebra, vertebra thoracica; right view

Fig. 22. Twelfth thoracic vertebra, vertebra thoracica; right view

Fig. 23. The thoracic part of the spinal column;
front view (radiograph).

1 - 1st rib; 2 - costal fossa;

3 - spinous process; 4 - transverse
process; 5 - the body of the 1st thoracic vertebra;

On the posterolateral surface of the bodies there are two facets: the superior costal fossa, fovea costalis superior, and the inferior costal fossa, fovea costalis inferior. The lower costal fossa of one vertebra forms a complete glenoid fossa with the upper costal fossa of the underlying vertebra - the place of articulation with the head of the rib.

The exception is the body of 1 thoracic vertebra, which has a complete costal fossa above, articulating with the head of 1 rib, and below - a half-well, articulating with the head of 2 ribs. On the 10th vertebra there is one half-frame, at the upper edge of the body; the bodies of the 11th and 12th vertebrae have only one complete costal fossa located in the middle of each lateral surface of the vertebral body.

The arcs of the thoracic vertebrae form a rounded vertebral foramen, but comparatively smaller than those of the cervical vertebrae.
The transverse process is directed outward and somewhat posteriorly and has a small costal fossa of the transverse process, fovea costalis processus transversus, articulating with the rib tubercle.

The articular surface of the articular processes lies in the frontal plane and is directed posteriorly at the superior articular process, and anteriorly at the lower. The spinous processes are long, triangular, pointed and directed downward. The spinous processes of the middle thoracic vertebrae are located one above the other in a tile-like manner.

The lower thoracic vertebrae in shape approach the lumbar vertebrae. On the posterior surface of the transverse processes of 11 - 12 thoracic vertebrae there is an accessory process, processus accessorius, and a mastoid process, processus mamillaris.

Lumbar vertebrae

The lumbar vertebrae, vertebrae lumbales (Fig. 24 - 27; see Fig. 7), number 5 (L1-L5), differ from others in their massiveness. The body is bean-shaped, the arches are strongly developed, the vertebral foramen is larger than that of the thoracic vertebrae, and has an irregularly triangular shape.

Fig. 24. Third lumbar vertebra, vertebra lumbalis; view from above

Fig. 25. Third lumbar vertebra, vertebra lumbalis; right view

Fig. 27. The lumbar part of the spinal column; Front view (radiograph).
1 - 12th thoracic vertebra; 2 - 12th rib;
3 - costal process; 4 - articular process;
5 - spinous process; 6 - articular process;
7 - 1st lumbar vertebra.

Fig. 28. Sacrum, os sacrum; front view (Pelvic surface, facies pelvica.)

Each transverse process, located in front of the articular, is elongated, compressed from front to back, goes laterally and somewhat posteriorly. Its most part - the costal process, processus costalis, - represents the rudiment of the rib. On the posterior surface of the base of the costal process, there is a weakly pronounced pre-6-side process, processus accessorius, a rudiment of the transverse process.

The spinous process is short and wide, thickened and rounded at the end. The articular processes, starting from the arch, are directed posterior to the transverse and are located almost vertically. The articular surfaces lie in the sagittal plane, with the upper concave and facing medially, and the lower convex and laterally directed.

When two adjacent vertebrae are articulated, the upper articular processes of one vertebra cover from the sides the lower articular processes of the other. On the postero-outer edge of the superior articular process there is a small mastoid process, processus mamillaris, - a trace of muscle attachment

Sacrum

The sacral vertebrae, vertebrae sacrales, number 5, grow together in an adult into a single bone - the sacrum.

The sacrum, os sacrum (sacrale) (Fig. 28 - 33; see Fig. 7), has the shape of a wedge, is located under the last lumbar vertebra and participates in the formation of the posterior wall of the small pelvis. In the bone, the pelvic and dorsal surfaces, two lateral parts, the base (the wide part facing upward) and the apex (the narrow part directed downward) are distinguished.

The anterior surface of the sacrum is smooth, concave, facing the pelvic cavity - this is the pelvic surface, the facies of the relvis (see Fig. 28). It retains traces of fusion of the bodies of the five sacral vertebrae in the form of four parallel transverse lines, line transversae. Outside of them, on each side, there are four anterior pelvic sacral foramina, foramina sacralia anteriora (pelvica) (the anterior branches of the sacral spinal nerves and their accompanying vessels pass through them).

Fig. 29 Sacrum, os sacrum; back view.
(Dorsal surface, facies dorsalis.)

The dorsal surface of the sacrum, facies dorsalis sacri (see Fig. 29), convex in the longitudinal direction, already anterior and rough. On it are located, five adjacent bony ridges going from top to bottom, formed as a result of the fusion of the spinous, transverse and articular processes of the sacral vertebrae.

Fig. 30 Sacrum, os sacrum; right view

Fig. 31 Sacrum, os sacrum; right side view.
(Mid-longitudinal cut.)

The median sacral crest, crista sacralis mediana, was formed from the fusion of the spinous processes of the sacral vertebrae and is represented by four tubercles located one above the other, sometimes merging into one rough crest.

On each side of the median sacral ridge, almost parallel to it, there is one weakly expressed intermediate sacral sinus, crista sacralis intermedia. The ridges are formed as a result of the fusion of the superior and inferior articular processes. Outside of them is a well-defined row of tubercles - the lateral sacral crest, crista sacralis lateralis, which is formed by the fusion of the transverse processes. Between the intermediate and lateral ridges, there are four posterior sacral foramina, foramina sacralia posteriora; they are somewhat smaller than the corresponding anterior sacral foramen (the posterior branches of the sacral nerves pass through them).

A sacral canal follows the entire length of the sacrum, canalis sacralis, curved, widened at the top and narrowed at the bottom; it is a direct continuation from top to bottom of the spinal canal. The sacral canal communicates with the sacral foramen through the intervertebral foramina within the bone, foramina intervertebralia (see Fig. 31).

The base of the sacrum, the basis ossis sacri (see Fig. 28, 33), has a transverse-oval depression - the junction with the lower surface of the body of the 5th lumbar vertebra. The anterior edge of the sacrum base at the junction with the 5th lumbar vertebra forms a protrusion - a promontorium (see Fig. 7), which protrudes strongly into the pelvic cavity. From the posterior part of the base of the sacrum, the upper articular processes, processus articulares superiores, 1 sacral vertebra go up. Their articular surfaces, facies articulares, are directed backward and medially and articulate with the lower articular processes of the 5th lumbar vertebra. The posterior edge of the base (arch) of the sacrum with the superior articular processes protruding above it limits the entrance to the sacral canal.

The apex of the sacrum, arech ossis sacri, is narrow, obtuse and has a small oval platform - the junction with the upper surface of the coccyx; here the sacrococcygeal joint is formed, articulatiosacrococcygea (see Fig. 224), well pronounced in young people, especially in women.
Behind the apex, on the posterior surface of the sacrum, the intermediate ridges end in two small protrusions directed downward - the sacral horns, cornua sacralia. The posterior surface of the apex and the sacral horns limit the outlet of the sacral canal - the sacral gap, hiatus sacralis.

The upper-outer part of the sacrum - the lateral part, pars lateralis, was formed by the fusion of the transverse processes of the sacral vertebrae.
The upper, flattened, triangular surface of the lateral part of the sacrum, the front edge of which passes into the boundary line, is called the sacral wing, ala sacralis (see Fig. 28, 32).

Fig. 32 Sacrum, os sacrum; view from above

Fig. 33 Sacrum, os sacrum. (Horizontal
cut at level 2 of the sacral vertebra.)

The lateral surface of the sacrum - the articular ear-shaped surface, facies auricularis (see Fig. 30), articulates with the surface of the same name ilium(see "Belt of the lower limb").

Posteriorly and medially from the ear-shaped surface is the sacral tuberosity, tuberositas sacralis, - a trace of attachment of the sacroiliac interosseous ligaments.

The sacrum in men is longer, narrower and more curved than in women.

Coccyx

The coccyx, os coccygis (Fig. 34, 35; see Fig. 7), is a bone that has grown together in an adult from 4-5, less often from 3-6 vertebrae.

The tailbone has the shape of a curved pyramid, the base of which is turned upward and the top is downward. The vertebrae that form it have only bodies. On 1 coccygeal vertebra, on each side, there are the remains of the upper articular processes in the form of small protrusions - the coccygeal horns, cornua coccygea, which are directed upward and connect to the sacral horns.

The upper surface of the coccyx is somewhat concave, connected to the apex of the sacrum through the sacrococcygeal joint.

Fig. 34 Coccyx, os coccygis. A - front view; B - rear view.

Fig. 35 Sacral and coccygeal parts of the spinal column (X-ray)
1 - 5th lumbar vertebra; 2 - sacrum;
3 - tailbone; 4 - pubic bone; 5 - pubic arch;
6 - ischium.

BONES OF THE BREAST

Pe6pa

Ribs, costae (Fig. 36 - 39), 12 pairs, are narrow, curved bone plates of various lengths, symmetrically located on the sides of the thoracic spine.

In each rib, a longer bony part of the rib, os costale, is distinguished, a short cartilaginous - costal cartilage, cartilago cosstalis, and two ends - the front, facing the sternum, and the posterior, facing the spinal column.

The bony part of the rib has a head, neck and body. The head of the rib, caput costae, is located at its vertebral end. It has the articular surface of the rib head, facies articularis capitis costae. This surface is divided into 2-10 ribs by a horizontally running ridge of the rib head, crista capitis costae, into an upper, smaller, and lower, large, part, each of which is respectively articulated with the costal fossa of two adjacent vertebrae.

The neck of the rib, collum costae, is the most narrowed and rounded part of the rib, carries on the upper edge the crest of the neck of the rib, crista colli costae (1 and 12 ribs do not have this ridge).

On the border with the body, 10 upper pairs of ribs on the neck have a small rib tubercle, tuberculum costae, on which the articular surface of the rib tubercle, facies articularis tuberculi costae, articulates with the transverse costal fossa of the corresponding vertebra.

Between the posterior surface of the rib neck and the anterior surface of the transverse process of the corresponding vertebra, a costal-transverse opening, foramen costotransversarium, is formed (see Fig. 44).
The rib body, corpus costae, extending from the tubercle to the sternal end of the rib, is the longest section of the bony part of the rib. At some distance from the tubercle, the body of the rib, bending strongly, forms an angle of the rib, angulus costae. At 1 rib (see Fig. 36, A) it coincides with the tubercle, and on the remaining ribs the distance between these formations increases (up to 11 ribs); body 12 does not form an edge. The body of the rib is flattened throughout. This makes it possible to distinguish two surfaces in it: the inner, concave, and the outer, convex, and two edges: the upper, rounded, and the lower, sharp. On the inner surface along the lower edge runs a rib groove, sulcus costae (see Fig. 37), where the intercostal artery, vein and nerve lie. The edges of the ribs describe a spiral, so the rib is twisted around its long axis.

At the anterior sternal end of the bony part of the rib there is a fossa with a slight roughness; costal cartilage is attached to it.

Costal cartilage, cartilagines costales (there are also 12 pairs), are a continuation of the bony parts of the ribs. From 1 to 11 ribs, they gradually lengthen and connect directly to the sternum. The upper 7 pairs of ribs are true ribs, costae verae, the lower 5 pairs of ribs are false ribs, costae spuriae, and the 11th and 12th ribs are oscillating ribs, costae fluitantes. The cartilages of the 8th, 9th and 10th ribs do not fit directly to the sternum, but each of them joins the cartilage of the overlying rib. Cartilage 11 and 12 ribs (sometimes 10) do not reach the sternum and with their cartilaginous ends lie freely in the muscles of the abdominal wall.

Some features have the first two and the last two pairs of ribs. The first rib, costa prima (1) (see Fig. 36, A), is shorter but wider than the rest, has almost horizontally located upper and lower surfaces (instead of the outer and inner at other ribs). On the upper surface of the rib, in the anterior section, there is a tubercle of the anterior scalene muscle, tuberculum m. scaleni anterioris (the place of attachment of the specified muscle). Outward and posterior to the tubercle lies a shallow groove of the subclavian artery, sulcus a. subclaviae (the trace of the artery of the same name that runs here, a. subclavia), behind which there is a small roughness (the place of attachment of the middle scalene muscle, i.e. scalenus medius). Anteriorly and medially from the tubercle, there is a weakly pronounced groove of the subclavian vein, sulcus v. subclaviae. The articular surface of the rib head 1 is not divided by a ridge; the neck is long and thin; the costal angle coincides with the rib tubercle.

The second rib, costa secunda (see Fig. 36, B), has a roughness on the outer surface - tuberosity of the anterior dentate muscle, tuberositas m. serrati anterioris (the place of attachment of the tooth of the specified muscle).

The eleventh and twelfth ribs, costa 11 et costa 12 (see Fig. 39), have the articular surfaces of the head not separated by the crest. On the 11th rib, the angle, neck, tubercle and costal groove are weakly expressed, and on the 12th they are absent.

Sternum

The sternum, sternum (Fig. 40, 41), is an unpaired elongated bone with a somewhat convex anterior surface and, accordingly, a concave posterior surface. The sternum occupies a section of the anterior chest wall. On it, a handle, a body and a xiphoid process are distinguished. All these three parts are interconnected by cartilaginous layers, which ossify with age.

The handle of the sternum, manubrium sterni, is the widest part, thick at the top, thinner and narrower at the bottom, has a jugular notch on the upper edge, incisura jugularis, easily palpable through the skin. On the sides of the jugular notch are the clavicular notches, incisurae claviculares, - the junction of the sternum with the sternal ends of the clavicles.

Slightly lower, on the lateral edge, is the notch of 1 rib, incisuga costalis, - the place of fusion with the cartilage of 1 rib. Even lower there is a small depression - the upper part of the rib notch 2 ribs; the lower portion of this notch is located on the body of the sternum.

The body of the sternum, corpus sterni, is almost 3 times longer than the handle, but narrower than it. The body of the sternum is shorter in women than in men.

Fig. 40 Sternum, sternum; front view

Fig. 41 Sternum, sternum; right view

The anterior surface of the sternum has traces of the fusion of its parts in the process of embryonic development in the form of weakly expressed transverse lines.

The cartilaginous connection of the upper edge of the body with the lower edge of the arm is called the synchondrosis of the arm of the sternum, synchondrosis manubriosternalis (see Fig. 235), while the body and arm converge, forming a blunt, posteriorly open angle of the sternum, angulus sterni. This protrusion is at the level of the junction of the 11 rib with the sternum and is easily felt through the skin.

On the lateral edge of the body of the sternum, four complete and two incomplete costal notches, incisurae costales, are distinguished - the places of articulation of the sternum with cartilage of 2 to 7 ribs. One incomplete notch is located at the top of the lateral edge of the sternum and corresponds to the cartilage of the 11th rib, the other is at the bottom of the lateral edge and corresponds to the cartilage of the 7th rib; four full cuts lie between them and correspond to 3 - 6 ribs.

The sections of the lateral sections lying between two adjacent costal notches are in the form of semi-lunar depressions.

The xiphoid process, processus xiphoideus, is the most short part sternum, can be different in size and shape, with a forked apex or with a hole in the middle. The sharp or blunt apex faces either anteriorly or posteriorly. In the upper-lateral part of the xiphoid process, there is an incomplete notch articulating with the cartilage of the 7th rib.

The xiphoid process forms with the body of the sternum a synchondrosis of the xiphoid process, synchondrosis xiphosternalis (see Fig. 235). By old age, the xiphoid process, ossified, grows together with the body of the sternum.

Sometimes, above the handle of the sternum, in the thickness of the subhyoid muscle group or in the medial pedicle of the sternocleidomastoid muscle, there are 1-3 breast bones, ossa suprasternalia. They articulate with the handle of the sternum.

RIB CAGE

The chest, compages thoracis (Fig. 42 - 45), is the thoracic spine, ribs (12 pairs) and sternum.

The thorax forms a chest cavity, cavitas thoracis, in the shape of a truncated cone, facing downward with a wide base, and a truncated apex upward.

Fig. 42 Chest, compages thoracis; front view

Fig. 43 Chest, compages thoracis; back view

In the chest, there are front, back and side walls, the upper and lower opening, which limit the chest cavity.

The anterior wall is shorter than the rest of the walls, formed by the sternum and cartilage of the ribs. Situated obliquely, it protrudes more anteriorly with its lower sections than with its upper ones. The back wall is longer than the front, formed by the thoracic vertebrae and sections of the ribs from the heads to the corners; its direction is almost vertical.

On the outer surface of the posterior wall of the chest, between the spinous processes of the vertebrae and the corners of the ribs, two grooves are formed on both sides - dorsal grooves; they contain deep muscles back. On the inner surface of the chest, between the protruding bodies of the vertebrae and the angles of the ribs, two grooves are also formed - pulmonary grooves, sulci pulmonales, the lungs adjoin them with the vertebral part of the costal surface (see Fig. 44).

Fig. 44 Chest segment (radiograph).
The ratio of the ribs to vertebra 4 and the sternum.

Fig. 45 Chest; front view.
1 - left clavicle; 2 - the descending aorta; 3 - gate
lung; 4 - pulmonary trunk; 5 - heart; 6 - left
lung; 7 - diaphragm (left dome); 8 - diaphragm
(right dome); 9 - ascending aorta; 10 - top
right lung; 11 - aortic arch; 12 - rib (back
part); 13 - right clavicle; 14 - right shoulder blade;
15 - left shoulder blade; 16 - rib (front part)

The side walls are longer than the front and back, formed by the bodies of the ribs and are more or less convex. The spaces bounded above and below by two adjacent ribs, in front by the lateral edge of the sternum and behind by the vertebrae, are called intercostal spaces, spatia intercostalia; they are made by ligaments, intercostal muscles and membranes.

The chest, compages thoracis, bounded by these walls, has two openings - the upper and lower, which are called apertures.

The upper aperture of the chest, apertura thoracis superior (see Fig. 133), is smaller than the lower one, bounded in front by the upper edge of the handle, from the sides by the first ribs and behind by the body of 1 thoracic vertebra. It has a transverse oval shape and is located in a plane inclined from back to front and downward. The upper edge of the sternum handle is at the level of the interval between the 2nd and 3rd thoracic vertebrae.

The lower aperture of the chest, apertura thoracis inferior, is bounded in front by the xiphoid process and the costal arch formed by the cartilaginous ends of the false ribs, from the sides - by the free ends of 11 and 12 ribs and the lower edges of 12 ribs, behind - by the body of the 12th vertebra.

The costal arch, arcus costalis, at the xiphoid process forms an open sub-sternal angle, angulus infrasternalis (see Fig. 42).

The shape of the chest varies from person to person (flat, cylindrical, or conical). In persons with a narrow chest, the sub-sternal angle is sharper and the intercostal space is wider, and the rib cage itself is longer than in persons with a wide chest. The rib cage in men is longer, wider and more tapered than in women. The shape of the chest also depends on age.

FIBROUS CONNECTIONS

Fibrous joints, articulationes fibrosae (Fig. 216), provide a continuous connection of bones due to various types of connective tissue: dense, connective, cartilaginous or bone tissue.

Fibrous joints formed by dense connective tissue include syndesmosis, sutures and hammering.

Syndesmoses, syndesmoses, include ligaments, which are junctions between bones built of dense connective tissue. For example, the pterygo-spinous ligament, lig. pterygospinale, starts from the spine of the sphenoid bone and is attached to the pterygo-spinous process located on the lateral plate of the pterygoid process; stylohyoid ligament, lig. stylohyoideum, thin and long, starts from the styloid process and, going down and anteriorly, attaches to the small horns of the hyoid bone, etc. Sometimes syndesmoses can contain a significant amount of elastic fibers, such as yellow ligaments, ligg. f1ava, located between the arches of the vertebrae, nuchal ligament, lig. nuchae, etc. In addition, syndesmosis are broad ligaments that connect bones over a considerable length: interosseous membranes of the forearm and lower leg, membrana interossea antebrachii, membrana interossea cruris. Syndesmosis also includes the fontanelles of the skull, built of primary connective tissue.

Seams, suturae, connect the bones of the cranial vault and face. They are formed by short strands of dense connective tissue that run between the edges of adjacent bones and penetrate into them. With age, ossification of the seams occurs due to the replacement of dense connective tissue with bone tissue. According to the relief of the seams and the method of applying the connecting edges of the bones, the following types of seams are distinguished: serrated seam, sutura serrata; scaly seam, sutura squamosa; flat seam, sutura plana. Scaly and serrated sutures connect the bones of the cranial vault. The bones of the face are often connected with a flat suture, which ensures accurate and even matching of the edges. In addition, there is a suture in the form of schindillosis (cleavage), schyndilesis, - this is the connection of the edge of one bone with the groove of the other, as in the formation of the wedge-vomiting suture sutura sphenovomeriana.

3uboalveolar connections, articulationes dentoalveolares (gomphosis), are found when the roots of the tooth, covered with periodontium, are connected to the alveolus. Here, cords of dense connective tissue hold the teeth in the dental alveoli. With age, this connection weakens, and the teeth become loose (see Vol. 2 "Digestive system").

Cartilage joints, articulationes cartilagineae, are a type of fibrous joints formed by cartilage tissue. Among the cartilaginous joints, synchondrosis and symphysis are distinguished.

Synchondrosis, synchondroses, are formed by continuous layers of cartilage connecting the edges of the bones and limiting movement. They are widespread in the skeletal system of children and adolescents - they connect parts of bones (for example, the diaphysis of a long bone with pineal glands, sacral vertebrae between themselves, etc.). These are fickle synchondrosis, with age, cartilage tissue is replaced by bone. Synchondrosis that persists in the adult skeleton includes synchondrosis of the skull (sphenoid-occipital, sphenoid-stony, stony-occipital, sphenoid-ethmoid) and synchondrosis of the sternum (synchondrosis of the handle and xiphoid process).

Fig. 216 Fibrous joints, articulationes fibrosae

Syndesmos, syndesmosis: 1a - yellow ligaments, ligg. flava; 1b - interosseous membrane of the forearm, membrana interossea antebrachii. Suture, sutura: 2a - serrated suture, sutura serrata; 2b - scaly suture, sutura squamosa; 2c - flat seam, sutura plana. Synchondrosis, synchondrosis: 3a - synchondrosis of the sternum handle, synchondrosis manubriosternalis; 3b - xiphoid process synchondrosis, synchondrosis xiphosternalis; 3c - sphenoid-occipital synchondrosis, synchondrosis sphenooccipitalis; 4 - dentoalveolar connection, gomphosis (articulatio dentoalveolaris). Symphysis, symphysis: 5а - intervertebral symphysis, symphysis intervertebralis; 5b - pubic symphysis, symphysis pubica.

Symphysis, symphyses, are formed by fibrous cartilage, and there is a cavity inside the cartilaginous plate. Such connections are observed between the vertebral bodies - the intervertebral symphysis, symphysis intervertebralis (see Fig. 219), the symphysis of the sternum handle, symphysis manubriosternalis, (see Fig. 235), and the pubic symphysis, symphysis pubica (see Fig. 259).

SYNOVIAL JOINTS (JOINTS)

Discontinuous joints of bones - joints, or synovial joints, articulationes synoviales (Fig. 217), are the most common type of articulation of human bones, creating conditions for high mobility of his body. A joint is called simple, articulatio simplex, if two bones are involved in its formation, and complex, articulatio composita, if it is formed by three or more bones.

Fig. 217. Synovial connections (joints). Types of joints according to the shape and number of axes of rotation. Uniaxial joints; 1a, 1b - block joints, ginglimus (a - articulatio talocruralis; b - articulatio interphalangea manus); 1c - cylindrical joint, articulatio trochoidea (articulation radioulnaris proximalis). Biaxial joints: 2a - elliptical joint, articulatio ellipsoidea (articulatio radiocarpea); 2b - condylar joint (articulatio genus); 2c - saddle joint, articulatio sellaris (articulatio carpometacarpea pollicis). Triaxial joints: 3a - spherical joint, ariculatio spheroidea (articulation humari); 3b - cup-shaped joint, articulatio cotylica (articulatio coxae); 3c - flat joint, articulatio plana (articulatio sacroiliaca).

Each joint has obligatory structural elements, without which the connection of bones cannot be attributed to joints, and auxiliary formations that determine the structural and functional differences of one joint from others.

TO required elements the joint includes the articular cartilage that covers the articular surfaces; articular capsule and articular cavity.

Articular cartilage, cartilago articulares, usually built of hyaline cartilage, less often fibrous. These cartilages cover the surfaces of the bones with which the articulating bones face each other. Consequently, one surface of the articular cartilage is fused with the surface of the bone covered by it, and the other will freely stand in the joint.

Articular capsule, capsula articularis, surrounds the articulating ends of the bones in the form of a closed cover and, without passing to the articular surfaces, continues into the periosteum of these bones. The capsule is built of fibrous connective tissue and consists of two layers - membranes. The outer, fibrous membrane, membrana fibrosa (stratum fibrosum), is built of dense fibrous connective tissue and performs a mechanical role. From the inside, it passes into the synovial membrane, membrana synovialis (stratum synoviale). The synovial membrane forms synovial folds, plicae synoviales. This membrane secretes into the joint synovial fluid (synovia), synovia, which wets the articular surfaces of the bones, nourishes the articular cartilage, acts as a shock absorber, and also changes the mobility of the joint as its viscosity changes. The working surface of the membrane increases not only due to synovial folds, but also due to synovial villi, vilii synoviales, facing the articular cavity.

Articular cavity, cavitas articularis, is a narrow closed gap, limited by the articulating surfaces of the bones and the articular capsule and filled with synovial fluid. The cavity does not communicate with the atmosphere.

Auxiliary joint formations are diverse. These include ligaments, ligamenta; articular discs, disci articulares; articular menisci, menisci articulares; articular lips, labra articularia.

Joint ligaments- These are bundles of dense fibrous connective tissue that strengthen the joint capsule and restrict or direct the movement of bones in the joint. In relation to the articular capsule, extracapsular ligaments, ligg, are distinguished. extracapsularia, located outside the joint capsule, capsular ligaments, ligg. capsularia, located in the thickness of the capsule, between its fibrous and synovial membranes, and intracapsular ligaments, ligg. intracapsularia, inside the joint. Almost all joints have ligaments. The extracapsular ligaments are woven into the outer sections of the fibrous layer of the capsule; the capsular ligaments are a thickening of this layer, and the intracapsular ligaments are intra-articular in their position, but are covered with a synovial membrane that separates them from the joint cavity.

Cyclic discs- These are layers of hyaline or fibrous cartilage wedged between the articular surfaces of the bones. They are attached to the joint capsule and divide the joint cavity into two levels. The discs increase the conformity (congruence) of the articular surfaces, and, consequently, the range and variety of movements. They also serve as shock absorbers to reduce shock and shock when driving. Such discs are found, for example, in the sternoclavicular and temporal joints.

Cystic menisci unlike discs, these are not solid cartilaginous plates, but sickle-shaped formations of fibrous cartilage. Two menisci, right and left, are in each knee joint; they are attached with the outer edge to the capsule, closer to the tibia, and with a sharp inner edge they freely stand in the joint cavity. Menisci diversify joint movements and serve as shock absorbers.

Articular lip formed by dense fibrous connective tissue. It attaches to the edge of the glenoid cavity and deepens it, increasing surface conformity. The lip faces the joint cavity (shoulder and hip joints).

Joints differ in the shape of the articular surfaces and the degree of mobility of the articulating bones. According to the shape of the articular surfaces, there are: spherical (cup-shaped) joints, articulationes spheroideae (cotylicae); flat, articulationes pianae; elliptical, articulationes ellipsoideae (condylares); saddle, articulationes sellares; ovoid, articulationes ovoidales; cylindrical, articulationes trochoideae; blocky, ginglymus; condylar, articulationes bicondylares.

The nature of movement in the joint depends on the shape of the articular surfaces (see Fig. 217). Spherical and flat joints, in which the generatrix is ​​represented by a segment of a circle, allow movement around three mutually perpendicular axes: frontal, anteroposterior (sagittal) and vertical. So, in the shoulder joint, spherical in shape, flexion (f1exio) and extension (extensio) are possible around the frontal axis, while movement occurs in the sagittal plane; around the anteroposterior axis - abduction (abductio) and adduction (adductio), the movement takes place in the frontal plane. Finally, rotation around the vertical axis is possible, (rotatio), including inward (pronatio) and outward (supinatio), and the rotation itself is carried out in the horizontal plane. These movements in flat joints are very limited (the flat articular surface in this case is considered as a small segment of a circle of large diameter), and in the spherical joints, movements are performed with a large amplitude and are supplemented by circular guidance (circumductio), in which the center of rotation corresponds to the spherical joint, and a moving bone describes the surface of a cone.

Joints in which movement around one of the three axes is excluded and is possible only around two axes are called biaxial... Biaxial joints include elliptical joints (for example, the wrist joint) and saddle joints (for example, the wrist joint of 1 finger of the hand).

Uniaxial and are considered cylindrical and blocky joints. In a cylindrical joint, the generatrix moves parallel to the axis of rotation. An example of such a joint is the atlanto-axial median joint, the axis of rotation in which runs vertically through tooth 2 of the cervical vertebra, as well as the proximal radioulnar joint.

A kind of uniaxial joint is block-shaped, in which the generatrix is ​​inclined with respect to the axis of rotation (as it were, beveled). These joints include the brachio-ulnar and interphalangeal joints.

Condylar joints, articulationes bicondylares, are modified elliptical joints.

In some joints of the skeletal system, movements are possible only simultaneously with movements in adjacent joints, i.e. anatomically isolated joints are united by a common function. This functional combination of joints must be taken into account when studying their structure and analyzing the structure of movements.

CONNECTIONS OF THE BODY AND SKULL

BONE CONNECTIONS

Vertebral column joints

Individual vertebrae, through connections of various types, are connected to each other, forming a vertebral column, columna vertebralis.
These connections are: cartilaginous connections, articulationes cartilagineae, forming the intervertebral symphysis, symphysis intervertebralis, represented by intervertebral discs, disci intervertebrales, connecting the vertebral bodies; joints of the spine, articulationes vertebrales, including facet joints, articulationes zygapophysiales, lumbosacral joint, articulatio lumbosacralis, and sacrococcygeal joint, articulatio sacrococcygea. All these joints are strengthened by a large number of ligaments stretched between bodies, arches and processes of the vertebrae, ligaments of the spinal column, ligg. columnae vertebralis.

Intervertebral symphysis

The intervertebral symphysis, symphysis intervertebralis (Fig. 218 - 221), is represented by intervertebral discs (cartilages) lying between the bodies of two adjacent vertebrae along the cervical, thoracic and lumbar sections of the vertebral column.

The intervertebral disc, discus intervertebralis (see Fig. 218 - 221, 225), belongs to the group of fibrous cartilage. It distinguishes between the peripheral part - the annulus fibrosus, anulus fibrosus, and the centrally located gelatinous nucleus, nucleus pulposus.

Fig. 218 Intervertebral discs, disci intervertebrales; front view

Fig. 219 Sagittal cut of the lumbar
vertebrae (L4 - L5) and intervertebral disc
(photo) .1 - annulus fibrosus, anulus fibrosus; 2 - nucleus pulposus, nucleus pulposus

In the orientation of the collagen fibers forming the annulus fibrosus, there are three directions: concentric, oblique (intersecting) and spiral. All fibers are lost at their ends in the periosteum of the vertebral bodies. The central part of the intervertebral disc - the nucleus pulposus - is very elastic and is a kind of springy layer, which, when the spine is tilted, shifts towards extension. On the cut of the intervertebral disc, the nucleus pulposus, compressed under normal conditions, protrudes above the surface of the annulus fibrosus. The gelatinous nucleus can be solid (see Fig. 225, A) or have a small slit cavity (see Fig. 225, B).
The transition of the annulus fibrosus to the nucleus pulposus is gradual. Towards the center of the disc in its tissue, the number of fibers in the intercellular substance decreases, but the mass of the basic substance increases. Until the age of 20, the nucleus pulposus is well expressed, and then, with age, it undergoes replacement with fibrous connective tissue growing from the annulus fibrosus. The intervertebral disc grows together with the hyaline cartilage covering the surfaces of the vertebral bodies facing each other, and its shape corresponds to the shape of these surfaces.There is no intervertebral disc between the atlas and the axial vertebra, The thickness of the discs is not the same and gradually increases towards the lower part of the spinal column, and the discs of the cervical and the lumbar spine in the front is somewhat thicker than in the back. In the middle part of the thoracic spine, the discs are much thinner than in the higher and lower parts. The cartilaginous region is a quarter of the length of the entire spinal column.

Facet joints

Facet joints, articulationes zygapophysiales (see, Fig. 220, 221, 226), are formed between the upper articular process, processus articularis superior, the underlying vertebra and the lower articular process, processus articularis inferior, the overlying vertebra. The articular capsule is strengthened along the edge of the articular cartilage. The articular cavity is located according to the position and direction of the articular surfaces, approaching in the cervical spine to the horizontal plane. in the thoracic region - to the frontal and in the lumbar region - to the sagittal plane. The facet joints in the cervical and thoracic regions of the spinal column belong to the flat joints in the lumbar - to the cylindrical ones. Functionally, they belong to the group of sedentary joints.

Symmetrical facet joints are combined joints, that is, those in which movement in one joint necessarily entails displacement in the other, since both joints are formations of articular processes on the same bone.

Ligaments of the spine, ligg. columnae verlebralis, can be divided into long and short (Fig. 222 - 227).

To the group of long ligaments spinal column include the following:

1.Anterior longitudinal ligament... lig. longitudinale anterius (see Fig. 221,224,226), runs along the anterior surface and partly along the lateral surfaces of the vertebral bodies along the length from the anterior tubercle of the atlas to the sacrum, where it is lost in the periosteum of the 1st and 2nd sacral vertebrae. The anterior longitudinal ligament in the lower parts of the spinal column is significant; wider and tighter. It loosely connects with the vertebral bodies and tightly with the intervertebral discs, since it is woven into the perichondrium covering them (perichondrium), perichondrium; on the sides of the vertebrae, it continues into their periosteum. The deep layers of the bundles of this ligament are somewhat shorter than the superficial ones, due to which they connect the adjacent vertebrae together, and the superficial, longer bundles lie along 4 - 5 vertebrae. The anterior longitudinal ligament limits excessive extension of the spinal column,

2. Posterior longitudinal ligament, lig. longitudinale posterius (Fig. 228; see Fig. 224, 227), located on the posterior surface of the vertebral bodies in the vertebral canal. It originates on the posterior surface of the axial vertebra, and at the level of the two upper cervical vertebrae continues into the integumentary membrane, membrana tectoria. Downward, the ligament reaches the initial section of the sacral canal. The posterior longitudinal ligament, in contrast to the anterior one, is wider in the upper spine than in the lower. It is firmly adhered to the intervertebral discs, at the level of which it is somewhat wider than at the level of the vertebral bodies. It connects loosely with the vertebral bodies, and the venous plexus lies in the connective tissue layer between the ligament and the vertebral body. The superficial bundles of this ligament, like the anterior longitudinal ligament, are longer than the deep ones.

A group of short ligaments of the spinal column is syndesmosis. These include the following ligaments:

2. Yellow ligaments, ligg. flava (Fig. 229; see Fig. 220, 223, 224), perform the intervals between the arches of the vertebrae from the axial vertebra to the sacrum. They are directed from the inner surface and the lower edge of the arch of the overlying vertebra to the outer surface and the upper edge of the arch of the underlying vertebra and, with their anterior edges, limit the intervertebral foramen behind.

Rice. 220. Facet joints; view from above
(III lumbar vertebra. Connections between II and III lumbar vertebrae; horizontal cut.)

Rice. 221. Ligaments and joints of the spinal column; right view

The yellow ligaments are composed of vertically extending elastic bundles that give them a yellow color. They reach their greatest development in the lumbar region. The yellow ligaments are very resilient and elastic, therefore, when the trunk is extended, they shorten and act like muscles, causing the body to be kept in a state of extension and thus reducing muscle tension. Flexion stretches the ligaments and thereby also reduces the tension of the trunk straightener (see back muscles). The yellow ligaments are absent between the arches of the atlas and the axial vertebra. Here, the integumentary membrane is stretched, which with its anterior edge limits the back of the intervertebral foramen through which the second cervical nerve exits.

2. Interspinous ligaments, ligg. interspinalia (see Fig. 221. 226) - thin plates that fill the intervals between the spinous processes of two adjacent vertebrae. They reach highest power in the lumbar spine and the least developed between the cervical vertebrae. In front, they are connected to the yellow ligaments, and behind, at the apex of the spinous process, they merge with the supraspinous ligament.

3. Supraspinous ligament, lig. supraspinale (see Fig. 221), is a continuous cord running along the tops of the spinous processes of the vertebrae in the lumbar and thoracic regions. At the bottom, it is lost on the spinous processes of the sacral vertebrae, at the top, at the level of the protruding vertebra (C7), it passes into the rudimentary nuchal ligament.

4. Outer ligament, lig. nuchae (see fig. 226), - a thin plate, consisting of elastic and connective tissue bundles. It is directed from the spinous process of the protruding vertebra (C7) along the spinous processes of the cervical vertebrae upward and, expanding somewhat, attaches to the external occipital ridge and the external, occipital ridge; has the shape of a triangle.
5. Intertransverse ligaments... ligg. intertransversaria (see Fig. 222), are thin bundles, poorly expressed in the cervical and partly thoracic regions and more developed, in the lumbar region. These are paired ligaments that connect the tops of the transverse processes of adjacent vertebrae and restrict lateral movements of the spine in the opposite direction. In the cervical region, they can be bifurcated or absent.

Fig. 222. Ligaments and joints of the spinal column, ligg. et articulations columnae vertebralis; back view. (Lumbar. The arches and processes of the 12 thoracic, 1 and 2 lumbar vertebrae are removed.)

The lumbosacral joint, articulatio lumbosacralis (see Fig. 224, 261), is formed between the 5th lumbar vertebra and the base of the sacrum. The joint is a modified intervertebral disc with an expanded cavity, the size of which is much larger than in the overlying discs (see Fig. 261). Above and below, the cavity extends to the hyaline plates covering the vertebral bodies. The intervertebral disc of this connection has a higher anterior edge, which, together with the base of the sacrum and the lower anterior part of the body of the 5th lumbar vertebra, forms a promontory (see Fig. 224). The lumbosacral joint is strengthened mainly by the ilio-lumbar ligament. lig. iliolumbale (see Fig. 259, 260), which goes from the posterior superior edge of the iliac fossa and the posterior third of the iliac crest and attaches to the anterolateral surface of the body of the 5th lumbar and 1 sacral vertebra. In addition, the joint is strengthened by the anterior and posterior longitudinal ligaments, which run down the anterior and posterior surfaces of the vertebral bodies, respectively.

Fig. 223. Ligaments of the spine, ligg.
columnae vertebralis; front view. (Lumbar
department. Front cut, removed
bodies 1 and 2 of the lumbar vertebrae.)

Fig. 224. Lumbosacral joint aticulatio
lumbosacralis, and sacrococcygeal
joint, articulatio sacrococcygea.
(Sagittal-median cut.)

Fig. 225. Intervertebral discs (N. Sak's specimen; photograph). (Horizontal sections at the level of the middle of the disc.) 1 - annulus fibrosus, annulus fibrosus; 2 - nucleus pulposus, nucleuspulposus; 3 - the cavity of the intervertebral disc of the lumbosacral joint.

Sacrococcygeal joint

The sacrococcygeal joint, articulatio sacrococcygea, is formed by the bodies of 5 sacral and 1 coccygeal vertebrae, connected by a modified intervertebral disc with an expanded cavity (see Fig. 224.261), This joint is strengthened by the following ligaments (see Fig. 224, 259, 260) :

1. Lateral sacrococcygeal ligament, lig. sacrococcygeum laterale, stretched between the transverse processes of the last sacral and 1 coccygeal vertebrae and is a continuation of the lig. intertransversarium.

2. Anterior sacrococcygeal ligament, lig. sacrococcygeum anterius (ventrale), is a continuation of lig. longitudinale anterius. It consists of two bundles located on the anterior surface of the sacrococcygeal joint. In the course, closer to the end of the tailbone, the fibers of these bundles intersect.

3. The superficial posterior sacrococcygeal ligament, lig.sacrococcygeum posterius superficiale (dorsale), stretches between the posterior surface of the coccyx and the side walls of the entrance to the sacral canal, covering its gap. It corresponds to the yellow and supraspinous ligaments of the spinal column.

4. Deep posterior sacrococcygeal ligament, lig. sacrococcygeum posterius (dorsale), profundum, is a continuation of lig. longitudinalis posterioris.

Synovial connections of the skull with atlas and atlas with the axial vertebra

Atlanto-occipital joint, articulatio atlanto-occipitalis (Fig. 230-232; see Fig. 227, 228), paired. Formed by the articular surface of the occipital condyles, condyli occipitales, and the superior glenoid fossa of the atlas, fovea articularis superior. The longitudinal axes of the articular surfaces of the occipital bone and the atlas somewhat converge anteriorly. The articular surfaces of the occipital bone are shorter than the articular surfaces of the atlas. The articular capsule is attached along the edge of the articular cartilage. In terms of the shape of the articular surfaces, this joint belongs to the group of ellipsoidal, or condylar, joints.

Fig. 226. Ligaments and joints of the spinal column, ligg. et articulationes columnae vertebralis; right view

In both, right and left, joints that have separate joint capsules, movements are performed simultaneously, i.e. they form one combined joint; nodding (bending forward and backward) and slight lateral movements of the head are possible.
In this connection, the following are distinguished:

1. Anterior atlanto-occipital membrane, membrana atlanto-occipitalis anterior (see fig. 226, 227). Stretches along the axes of the gap between the anterior edge of the foramen magnum and the upper edge of the anterior arch of the atlas; fuses with the upper end of the lig. longitudinale anterius. Behind her is the anterior atlantooccipital ligament, lig. atlanto-occipitalis anterior, stretched between the occipital bone and the middle part of the anterior arch of the atlas.

Fig. 227. Ligaments and joints of the cervical vertebrae and the occipital bone; inside view. (Sagittal-median cut through the occipital bone and 1-4 cervical vertebrae.)

2. Posterior atlanto-occipital membrane, membrana atlanto-occipitalis posterior (see fig. 226, 227, 229). Located between the posterior edge of the foramen magnum and the upper edge of the posterior arch of the atlas. In the anterior section, it has a hole through which blood vessels and nerves pass. This membrane is a modified ligamentum flavum. The lateral sections of the membrane are the lateral atlantooccipital ligaments, ligg. atlanto-occipitalis lateralia.
When the atlas and the axial vertebra are articulated, three joints are formed - two paired and one unpaired.

The lateral atlantoaxial joint (see Fig. 226, 231), paired, is formed by the lower articular surfaces of the atlas and the upper articular surfaces of the axial vertebra. It belongs to the type of sedentary joints, since its articular surfaces are flat and even. In this joint, sliding occurs in all directions of the articular surfaces of the atlas in relation to the axial vertebra.

The median atlanto-axial joint, articulatio atlanto-axialis mediana (see Fig. 227.228, 230, 232), is formed between the posterior surface of the anterior arch of the atlas (fovea dentis) and the tooth of the axial vertebra. In addition, the posterior articular surface of the tooth forms a joint with the transverse ligament of the atlas, lig. transversum atlantis.

Tooth joints belong to the group of cylindrical joints. In them, rotation of the atlas together with the head around the vertical axis of the tooth of the axial vertebra is possible, i.e., the head turns to the right and to the left.

Fig. 228. Ligaments and joints of the cervical vertebrae and the occipital bone; inside view. (Frontal cut, the posterior parts of the occipital bone and the arch of 1-5 cervical vertebrae were removed.)

Fig. 229. Ligaments of the cervical vertebrae and occipital bone; back view

The ligamentous apparatus of the median atlantoaxial joint includes:

1. Covering membrane, membrane tectoria (see Fig. 227, 230, 232), which is a wide, rather dense fibrous plate stretched from the anterior edge of the foramen magnum toward the body of the axial vertebra. This membrane is called the integumentary membrane because it covers the back (from the side of the spinal canal) the tooth, the transverse ligament of the atlas and other formations of this joint. It is considered as part of the posterior longitudinal ligament of the spinal column.

Fig. 230. Ligaments and joints of the cervical vertebrae and the occipital bone; inside view. (The posterior occipital bone and the posterior arch of the atlas have been removed.)

Fig. 231. Ligaments and joints of the cervical vertebrae and the occipital bone; inside view

2. Cruciate ligament of the atlas, lig. cruciforme atlantis (see Fig. 230) consists of two bundles - longitudinal and transverse. The transverse bundle is a dense connective tissue cord stretched between the inner surfaces of the lateral mass of the atlas. It adjoins the posterior articular surface of the axial vertebra tooth and strengthens it. This bundle is called the transverse ligament of the atlas, lig. transversum atlantis (see fig. 230, 232). Longitudinal beams. fasciculi longitudinales, consist of two, upper and lower, legs. The superior leg extends from the middle part of the transverse ligament of the atlas and reaches the anterior surface of the foramen magnum. The lower pedicle, which also starts from the middle part of the transverse ligament, goes down and attaches to the posterior surface of the axial vertebral body.

Fig. 232. Ligaments and joints of the atlas and the axial vertebra; view from above. (Horizontal cut, partially removed the anterior arch and lateral atlas masses, and the tooth of the axial vertebra.)

3. Ligament of the tooth apex, lig. apicis dentis (see Fig. 227, 231), stretches between the apex of the axial vertebra tooth and the middle part of the anterior margin of the greater occipital
holes. This ligament is considered as, a rudiment of a dorsal string (chord).

4. Pterygoid ligaments, ligg. alaria (see Fig. 230, 231), formed by bundles of connective tissue fibers stretched between the lateral surfaces of the tooth of the axial vertebra and the inner surfaces of the occipital condyles, condyli occipitales.

Chest joints

The ribs are connected movably with their posterior ends with the bodies and transverse processes of the thoracic vertebrae through the costal-vertebral joints, articulationes costovertebrales, the front ends - with the sternum, sternocostal joints, articulationes, sternocostales.

Costal-vertebral joints

The posterior ends of the ribs are articulated with the vertebrae using two joints:

1. The joint of the head of the rib, articulatio capitis costae (Fig. 233; see Fig. 236), is formed by the articular surface of the head of the rib and the costal fossa of the vertebral bodies. The heads from 2 to 10 ribs are conical and in contact with the corresponding articular fossa of the bodies of two vertebrae.

The articular surfaces on the vertebral bodies in most cases are formed by two pits: the smaller upper costal fossa, fovea costalis superior, which is located in the lower part of the body of the overlying vertebra, and the larger lower costal fossa, fovea costalis inferior, lying at the upper edge of the vertebra located below. Ribs 1, 11 and 12 are articulated only with the fossa of one vertebra. The articular surfaces of the costal fossa of the vertebrae and the heads of the ribs are covered with fibrous cartilage.

Fig. 233. Ligaments and joints of the ribs and vertebrae; view from above. (Horizontal cut, part 8 of the thoracic vertebra and 8 of the right rib removed.)

In the joint cavity of 2-10 ribs lies the intra-articular ligament of the rib head, lig. capitis costae intraarticulare. It goes from the ridge of the rib head to the intervertebral disc and divides the joint cavity into two chambers. The articular capsule is thin and is supported by the radiant ligament of the rib head, lig. capitis costae radiatum, which originates from the anterior surface of the rib head and attaches: fan-shaped to the above and below the vertebrae and the intervertebral disc.

2. Costal-transverse joint, articulatio coostotransversaria, (Fig. 234; see Fig. 233, 236), is formed by the articulation of the articular surface of the rib tubercle, facies articularis tuberculi costae, with the costal fossa of the transverse processes of the thoracic vertebrae. These joints are available only in 10 upper ribs. Their articular surfaces are covered with hyaline cartilage. The articular capsule is thin and is attached along the edge of the articular surfaces.
The joint is strengthened with numerous ligaments:
a) superior costal-transverse ligament, lig. costotransversarium superius, originates from the lower surface of the transverse process and attaches to the crest of the neck of the underlying rib;
b) lateral costal-transverse ligament, lig. costotransversarium laterale, stretched between the bases of the transverse and spinous processes and the posterior surface of the neck of the underlying rib;
c) costal-transverse ligament, 1ig. costotransversarium, lies between the posterior surface of the rib neck and the anterior surface of the transverse process of the corresponding vertebra, filling the costal foramen, foramen costotransversarium (see Fig. 44, 233);
d) lumbar-costal ligament, lig. lumbocostale, - a thick fibrous plate stretched between the costal processes L1 and L2 and the lower edge of the 12 rib. It fixes the rib and at the same time strengthens the aponeurosis of the transverse abdominal muscle.

The joints of the head and tubercle of the rib are cylindrical joints in shape, and they are functionally connected: during the act of breathing, movements occur simultaneously in both joints.

Fig. 234. Ligaments and joints of the ribs and vertebrae; back view

Sternocostal joints

The front ends of the ribs end in costal cartilages. The bony part of the ribs is connected to the costal cartilage through the costochondral joints, articulationes costochondrales,
(Fig. 235), and the periosteum of the rib continues into the perichondrium of the corresponding costal cartilage, and the very connection between them is impregnated with lime with age. Costal cartilage of 1 rib grows together with the sternum. The costal cartilages of 2-7 ribs are articulated with the costal notches of the sternum, forming the sternocostal joints, articulationes sternocostales (Fig. 236; see Fig. 235). The cavity of these joints is a narrow, vertically located gap, which in the cavity of the joint 2 of the costal cartilage has an intra-articular sternocostal ligament, lig. sternocostale intraarticulare. It goes from the costal cartilage of 2 ribs to the junction of the arm and the body of the sternum. In the cavities of other sternocostal joints, this ligament is weak or absent.

The articular capsules of these joints, formed by the perichondrium of the costal cartilage, are strengthened by the radiant sterno-re6er ligaments, ligg. sternocostalia radiata, of which the anterior ones are more powerful than the posterior ones. These ligaments go radially from the end of the costal
cartilage to the anterior and posterior surfaces of the sternum, forming crosses and bindings with the ligaments of the same name on the opposite side, as well as with the above and underlying ligaments. As a result of this, a strong fibrous layer covering the sternum is formed - the membrane of the sternum, membrana sterni.

Fig. 235. Ligaments and joints of the ribs and sternum; front view. (Frontal cut, on the left, the anterior sections of the ribs and sternum are partially removed.)

The bundles of fibers that follow from the anterior surface of the 6-7 costal cartilages obliquely downward and medially to the xiphoid process form the pe6er-xiphoid ligaments, ligg. costoxiphoidea.

In addition, the outer and inner intercostal membranes are located in the intercostal spaces (see Fig. 234, 235).

The outer intercostal membrane, membrana intercostalis externa, lies on the front surface of the chest in the region of the costal cartilage. The bundles that make it start from the lower edge of the cartilage and, going obliquely down and anteriorly, end at the upper edge of the underlying cartilage. The internal intercostal membrane, membrana intercostalis interna, is located in the posterior parts of the intercostal space. Its bundles start from the upper edge of the rib and, going obliquely up and anteriorly, are attached to the lower edge of the overlying rib. In the areas where the membrane is located, intercostal muscles are absent. Both membranes strengthen the intercostal space.

Costal cartilage from 5 to 9 ribs are interconnected by means of dense fibrous tissue and interchondral joints, articulationes interchondrales.

Fig. 236. Ligaments and joints of the ribs, vertebrae and sternum; view from above. (The connection of the 5th pair of ribs with the 5th thoracic vertebra and the corresponding segment of the sternum.)

LOWER LIMB JOINTS

The joints of the lower limb, articulationes membri inferioris, are subdivided into the joints of the girdle of the lower limb, articulationes cinguli membri inferioris, and the joints of the free lower limb, articulationes membri inferioris liberi.

LOWER LIMB JOINTS

The bones of the girdle of the lower limb are connected by means of two sacroiliac joints, the pubic symphysis of a number of ligaments.

KresTiliac joint

The sacroiliac joint, articulatio sacroiliaca (rice, 259-261), is a paired joint formed by the ilium and the sacrum.

The articular auricular surfaces, facies auriculares, ilia and sacrum are flat, covered with fibrous cartilage. The articular capsule is attached along the edge of the articular surfaces and is tightly stretched. The ligamentous apparatus is represented by strong, highly stretched fibrous bundles located on the anterior and posterior surfaces of the joint. On the front surface of the joint are the anterior sacroiliac ligaments, ligg. sacroiliaca anteriora (ventralia). They are bark bundles of fibers running from the pelvic surface of the sacrum to the ilium.

There are several ligaments on the back of the joint:

1. Interosseous sacroiliac ligaments, ligg. sacroiliaca interossea, lie behind the sacroiliac joint, in the interval between the bones forming it, attaching at their ends to the iliac and sacral tuberosities.

2. Posterior sacroiliac ligaments, ligg. sacroiliaca posteriora (dorsalia). Separate bundles of these ligaments, starting from the lower posterior iliac spine, are attached to the lateral sacral ridge at the level of 2-3 sacral foramen. Others follow from the superior posterior iliac spine downward and somewhat medially, attaching to the posterior surface of the sacrum in the region of the 4th sacral vertebra.

Fig. 259. Ligaments and joints of the pelvis; view from above. (Ligaments and joints of the lower limb girdle, lig. Et articulationes cinguli membri inferioris. Horizontal and sagittal cuts. Part of the left pelvic bone, left sacrum and 4-5 lumbar vertebrae were removed.

Fig. 260. Ligaments and joints of the pelvis, hip joint, articulatio coxae; back view. (The joint capsule of the left hip joint has been removed.)

Fig. 261. Ligaments and joints of the pelvis, right side; inside view.
(Sagittal-median cut)

The sacroiliac joint is a sedentary joint.
The pelvic bone, in addition to the sacroiliac joint, is connected to the spinal column through a series of powerful ligaments, which include the following:
1. Sacro-tuberous ligament, lig. sacrotuberale (see fig. 259-261), starts from the medial surface of the ischial tuberosity and, heading up and medially, expands fan-like; attached to the outer edge of the sacrum and coccyx. Part of the fibers of this ligament passes to the lower part of the ischial branch and, continuing along it, forms a falciform process, porcessus falciformis.
2. Sacrospinous ligament, lig. sacrospinale (see Fig. 259-261), starts from the ischial spine, goes medially and posteriorly and, located in front of the previous ligament, is attached along the edge of the sacral bone and partly the coccyx. Both ligaments, together with the large and small sciatic notches, limit two openings: the large sciatic, foramen ischiadicum majus, and the small ischial, foramen ischiadicum minus. Muscles emerging from the pelvis, as well as vessels and nerves, pass through these holes.
3. Iliolumbar ligament, lig. iliolumbale (see Fig. 259, 260), starts from the anterior surface of the transverse processes of the 4th and 5th lumbar vertebrae, goes outward and attaches to the posterior parts of the iliac crest and the medial surface of the wing of the ilium. This ligament strengthens the lumbosacral joint, articulatio lumbosacralis.

Pubic symphysis

The pubic symphysis, the symphysis of the annulus (see Figs. 259, 261), is formed by the articular surfaces of the pubic bones, jacies symphysiales, covered with hyaline cartilage, and the fibrocartilaginous interpubic disc located between them, the discus interpubicus. The specified disc grows together with the articular surfaces of the pubic bones and has a sagittally located slit cavity in its thickness. In women, the disc is somewhat shorter than in men, but thicker and has a relatively large cavity.

The following ligaments are strengthened by the pubic symphysis:
1. Superior pubic ligament, lig. pubicum superius, which is located on the upper edge of the symphysis and stretched between both pubic tubercles.
2. The arcuate ligament of the pubis, lig. arcuatum pubis, which passes from one pubic bone to another at the lower edge of the symphysis.

The own ligaments of the pelvis include the obturator membrane, membrana obturatoria (Fig. 262; see Fig. 260.261) which consists of bundles of connective tissue fibers, mainly in the transverse direction. The tufts are attached along the edge of the obturator opening, performing it throughout, with the exception of the obturator groove. The blocking diaphragm has a series of small holes. She and the muscles starting from it, together with the obturator groove, limit the obturator canal, canalis obturatorius, through which the vessels and nerves of the same name pass.

JOINTS OF FREE LOWER LIMBS

Hip joint

The hip joint, articulatio sohae, (Fig. 263-265; see Fig. 260, 262), is formed by the articular surface of the femoral head, which is covered with hyaline cartilage throughout, with the exception of the fossa, and the acetabulum of the pelvic bone.
The acetabulum is covered with cartilage only in the region of the lunar surface, and the rest of the length is made of fatty tissue and covered with a synovial membrane. Above the notch of the acetabulum….

Muscles of the spine

The muscles of the spine (deep back muscles) are arranged in three layers.
1. Erector spine, m. erector spinae (Fig. 296, 297), located most superficially and is the most powerful and longest muscle of the back; it fills the entire length of the back with a depression on the sides from the spinous processes to the corners of the ribs (see Fig. 43). The muscle begins from the posterior iliac crest, the dorsal surface of the sacrum, the spinous processes of the lower lumbar vertebrae and partly from the superficial leaflet of the lumbar-thoracic fascia. Heading up, the muscle divides into lumbar region into three parts: laterally located ileal-re6ernaya muscle, medial-spinous muscle, and between them is the longest muscle.
a) iliocostal muscles a, m. iliocostalis (see Fig. 295-297), with numerous muscle and tendon teeth, attaches to the corners of all ribs and the transverse processes of the lower cervical vertebrae. The following muscles are topographically distinguished:
NS iocostal muscle lower back, m. iliocostalis lumborum, originates from the posterior part of the lateral sacral ridge and lumbar-thoracic fascia and, going to the side and up, forms 8 - 9 teeth, which are attached to the corners of the eight to nine lower ribs with thin narrow tendons;
iliocostal muscle of the chest, m. iliocostalis thoracis, starting near the corners of the lower five to six ribs, follows slightly obliquely upward and outward and attaches with thin narrow tendons to the corners of the upper five to seven ribs;
iliocostal muscle of the neck, m. iliocostalis cervicis, starts from the corners of five to seven upper ribs, is also directed obliquely upward and laterally, and attaches with three teeth to the posterior tubercles of the transverse processes of the 4th, 5th and 7th cervical vertebrae.

Fig. 296. Muscles of the back, neck and suboccipital muscles.
(Deep muscles of the back are long: the second superficial layer.)

Innervatsi me: rr. dorsales nn. spinales (C3-C5; Th1-L1).
b) longest muscle, m. longissimus (see Fig. 295-297), located medially from the iliocostal muscle, extending from the sacrum to the base of the skull. Topographically, they differ in:
longest muscle of the chest, m. longissimus thoracis, which starts from the posterior surface of the sacrum, the transverse processes of the lumbar and lower six to seven thoracic vertebrae and. following up, it attaches to the corners of the ten lower ribs and to the posterior sections of the transverse processes of all thoracic vertebrae;
longest muscle of the neck, m. longissimus cervicis, originates from the transverse processes of four to five upper thoracic and lower cervical vertebrae and. going up, it is attached to the transverse processes of the vertebrae from the axial to the 5th cervical;
longest muscle of the head, m. longissimus capitis. starts from the transverse processes of the three upper thoracic and three to four lower cervical vertebrae, goes up and attaches to the posterior edge of the mastoid process.

Innervation: rr. dorsales nn. spinales (C1 - S2)
c) Spinous muscle, m. spinalis (see Fig. 295-297), is located along the spinous processes and is topographically divided into a number of muscles:

Fig. 297. Places of origin and attachment of the back muscles (diagram)

O pectoralis muscle, m. spinalis thoracis. starts from the spinous processes of two or three upper lumbar and two or three lower thoracic vertebrae and, heading up, is attached to the spinous processes of 8 - 2 thoracic vertebrae;
spinous muscle of the neck m. spinalis cervicis, originates from the spinous processes of the two upper thoracic and two lower cervical vertebrae and, following upward, ends on the spinous processes of the upper cervical vertebrae - from 4 to 2;
spinous muscle of the head, m. spinalis capitis, a poorly developed section of the spinous muscle, sometimes part of m. semispinalis capitis or absent. It starts from the spinous processes of the upper thoracic and lower cervical vertebrae, goes up and is attached near the external occipital protuberance.
Function: the entire muscle that straightens the spine, m. erector spinae, with bilateral contraction, is a powerful extensor of the spinal column, keeps the trunk in an upright position. With a unilateral contraction, it tilts the spinal column in the appropriate direction. The upper bundles of muscles pull the head in their direction. With part of her beams (m. Iliocostalis thoracis), she lowers the ribs.
Innervation: nn. spinales (C1 - S2).
2. Transverse spinous muscle m. transversospinalis (Fig. 298-300), covered by m. erector spinae and fills the cavity between the spinous and transverse processes along the entire spinal column. Relatively short muscle bundles have an oblique direction, they are thrown from the transverse processes of the underlying vertebrae to the spinous processes.

Fig. 298. Back muscles back area neck and suboccipital muscles.
(Deep muscles of the back: first and second layers.)

overlying. According to the length of the muscle bundles, that is, according to the number of vertebrae through which the muscle bundles are thrown, three parts are distinguished in the transverse spinous muscle:
a) semispinal muscles y, the bundles of which are thrown over 5-6 vertebrae or more; it is located more superficially;
b) multiparticulate muscles, the bundles of which are thrown over 2-4 vertebrae; they
covered with a semi-spinal muscle;

v) rotator muscles, the bundles of which occupy the deepest position and are attached to the spinous process of the overlying vertebra or are transferred to the next overlying vertebra.

a) Semispinal muscle, m. semispinalis (see Fig. 298-300), topographically divided into the following parts:
semispinal muscle of the chest, m. semispinalis thoracis, located between the transverse processes of the six lower and spinous processes of the seven upper thoracic vertebrae; in this case, each bundle is thrown over five to seven vertebrae;
semi-spinal muscle of the neck, m. semispinalis cervicis, lies between the transverse processes of the upper thoracic and spinous processes of the six lower cervical vertebrae. Its bundles are thrown over two to five vertebrae;

semispinal muscle of the head s, m. semispinalis capitis, lies between the transverse processes of the five upper thoracic vertebrae and 3-4 lower cervical vertebrae on one side and the nuchal area of ​​the occipital bone on the other. In this muscle, the lateral and medial parts are distinguished; the medial part in the muscular abdomen is interrupted by a tendon bridge.

Function: with the contraction of all beams, the muscle unbends the upper sections of the spinal column and pulls the head backward or holds it in the thrown position; with unilateral contraction, slight rotation occurs.
Innervation: rr. dorsales nn. spinales (C2 - C5; Th1 - Th12)
b) Multipart muscles, mm. multifidi (Fig. 301; see Fig. 298-300), covered with semi-awned, and in the lumbar region - with the lumbar part longest muscle... Bundles of muscles are located along the entire length of the spinal column between the transverse and spinous processes of the vertebrae (up to 2 cervical), throwing over 2, 3 or 4 vertebrae. Muscle bundles start from the posterior surface of the sacrum, the posterior segment of the iliac crest, the mastoid processes of the lumbar, transverse processes of the thoracic and articular processes of the four lower cervical vertebrae; end on the spinous processes of all vertebrae, except for the atlas.

Fig. 299. Places of origin and attachment of the muscles of the trunk (diagram)

(Deep muscles of the back: second deep layer.)

Innervation: mm. dorsales nn. spinales (C2 - S1)

v) Rotator muscles, mm. rotatores (see fig. 299-301), are the deepest part of the transverse spinous muscles and are topographically divided into rotators of the neck, mm. rotatores cervicis, rotators of the chest, mm. rotatores thoracis, and lumbar rotators, mm. rotatores lumborum.

They start from the transverse processes of all vertebrae, except for the atlas, and from the mastoid processes of the lumbar vertebrae. Throwing over one vertebra, they attach to the spinous processes of the overlying vertebrae, to the adjacent segments of their arcs and to the base of the arches of adjacent vertebrae.

Fig. 300. Muscles of the back and suboccipital muscles.
(Deep muscles of the back: the second and third layers.)

Function: the transverse spinous muscle with bilateral contraction unbends the spinal column, and with unilateral rotation it rotates in the direction opposite to the contracting muscle.
Innervation: nn. spinales (C2 - L5)
3. Interspinous muscles, mm. interspinales (see Fig. 297, 298, 300, 301), are short paired muscle bundles stretching between the spinous processes of two adjacent vertebrae. The interspinous muscles are located along the entire spinal column, with the exception of the sacrum. There are interspinous muscles of the neck, mm. interspinales cervicis, interspinal muscles of the chest, mm. interspinales thoracis (often absent), interspinal muscles of the lower back, mm. interspinales lumborum.
Function: unbend the spinal column and keep it in an upright position.
Innervation: rr. dorsales nn. spinales (C3 - L5)
4. Intertransverse muscles, mm. intertransversarii (see Fig. 298-301), short muscles, stretch between the transverse processes of two adjacent vertebrae. Distinguish between the back and front intertransverse muscles of the neck, mm. intertransversarii posteriors et anteriores cervicis, intertransverse muscles of the chest, mm. intertransversarii thoracis; lateral and medial intertransverse muscles of the lower back, mm. intertransversarii laterales et mediales lumborum.
Function: hold the spinal column, and with a one-sided contraction, tilt it to the side.
Innervation: rr. dorsales nn. spinales (C1 - C6; L1 - L4)
Blood supply: blood is delivered to all deep muscles of the back. occipitalis, cervicalis profundus, intercostales posteriores; aa. lumbales.

Fig. 301. Places of origin and attachment of the back muscles (diagram). (Deep back muscles: second deep layer. Short muscles back of the neck.)

Back fascia

There are three fasciae of the back.

1. Superficial fascia of the back- a thin connective tissue sheet, part of the common subcutaneous fascia, covers superficial muscles back.

2. Nuchal fascia, fascia nuchae, is located in the back of the neck, between the superficial and deep layers of muscles. Medially, it fuses with the nuchal ligament (see Fig. 295), laterally passes into the superficial layer of the fascia of the neck, at the top it is attached to the superior nuchal line.

3. Lumbar-thoracic fascia, fascia thoracolumbalis (see Fig. 294, 295, 298, 300), forms a dense fibrous sheath, in which the deep muscles of the back lie. This fascia consists of two layers - deep (anterior) and superficial (posterior). A deep leaf of the lumbar-thoracic fascia is stretched between the transverse processes of the lumbar vertebrae, the iliac crest and the 12th rib. It is present only in the lumbar region and lies in the interval between square muscle lower back, m. quadratus lumborum, and a muscle that straightens the spine, m. erector spinae.

The superficial leaflet of the lumbar-thoracic fascia is attached below to the iliac crests, laterally reaches the corners of the ribs and medially attached to the spinous processes of all vertebrae, except for the cervical. It reaches its greatest thickness in the lumbar region, in the upper sections it becomes significantly thinner. Laterally, along the lateral edge of m. erectoris spinae, the superficial leaf grows together with the deep one. In this way, a fibrous sheath is formed, in which the lumbar part of m lies. erectoris spinae; the upper sections of this muscle are located in the osteo-fibrous sheath of the back.