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TAZ IN GENERAL

Pelvis(pelvis) is formed by the connecting pelvic bones and the sacrum. It is a bone ring (Fig. 111). The pelvis is home to many internal organs. With the help of the pelvic bones, the trunk is connected with the lower limbs. There are two sections - a large and a small pelvis.

Big pelvis(pelvis major) is delimited from the lower pelvis by a border line. Border line(linea terminаlis) passes through the promontory of the sacrum, along the arcuate lines of the iliac bones, the crests of the pubic bones and the upper edge of the pubic symphysis. The large pelvis is bounded behind by the body of the V lumbar vertebra, from the sides - by the wings of the iliac bones. In front of a large pelvis bone wall does not have.

Small pelvis(pelvis minor) behind it is limited by the pelvic surface of the sacrum and the ventral surface of the coccyx. On the side, the walls of the pelvis are the inner surface of the pelvic bones (below the borderline), sacrospinous and sacro-tuberous ligaments. The front wall of the small pelvis is the upper and lower branches of the pubic bones, the pubic symphysis.

The small basin has an inlet and outlet. Upper aperture (hole) of the pelvis(apertura pelvis superior) is bounded by the border line. Exit from the pelvis - lower pelvic aperture(apertura pelvis inferior) behind it is limited by the coccyx, from the sides by sacro-tuberous ligaments, branches of the ischial bones, ischial tubercles, lower branches of the pubic bones, and in front by the pubic symphysis. The obturator opening located in the lateral walls of the small pelvis is closed by a fibrous obturator membrane(membrana obturatoria). Throwing over the obturator groove, the membrane limits obturator channel(canalis obturatorius). Vessels and a nerve pass through it from the pelvic cavity to the thigh. In the lateral walls of the small pelvis there are also a large and small sciatic foramen. Large sciatic foramen(forаmen ischiаdicum majus) is limited to the large sciatic notch and the sacrospinous ligament. Lesser sciatic foramen(forаmen ischiаdicum minus) is formed by a small sciatic notch, sacro-tuberous and sacrospinous ligaments.

Rice. 111. Male (A) and female (B) pelvis. The lines of the sizes of the large pelvis and the entrance to the small pelvis are indicated. 1 - distаntia cristаrum (distance between the iliac crests); 2 - transverse diameter; 3 - distаntia spinаrum (distance between the anterior superior iliac spines); 4 - true (gynecological) conjugate; 5 - oblique diameter.

The structure of the pelvis is associated with a person's gender. The upper aperture of the pelvis with the vertical position of the body in women forms an angle of 55-60 ° with the horizontal plane (Fig. 112). The pelvis in women is lower and wider, the sacrum is wider and shorter than in men. The promontory of the sacrum in women protrudes less forward. The ischial tubercles are more turned to the sides, the distance between them is greater than in men. The angle of convergence of the lower branches of the pubic bones in women is 90 ° (pubic arch), in men it is 70-75 ° (subpubic angle).

Rice. 112. Dimensions female pelvis... (Cut in the sagittal plane.) 1 - anatomical conjugate; 2 - true (gynecological) conjugate; 3 - straight size (exit from the pelvis); 4 - diagonal conjugate; 60 ° - the angle of inclination of the pelvis.

For forecasting generic process it is important to know the size of the woman's pelvis. The sizes of both the small and large pelvis are of practical importance. The distance between the two top and front iliac spines(distаntia spinаrum) in women is 25-27 cm.The distance between the most distant points of the wings iliac bones(distаntia cristаrum) is equal to 28-30 cm.

Direct size of the entrance to the small pelvis ( true, or gynecological, conjugate- conjugata vera, s. gynaecologica) is measured between the promontory of the sacrum and the most protruding posterior point of the pubic symphysis. This size is 11 cm.The transverse diameter (diameter transvérsa) of the entrance to the small pelvis - the distance between the most distant points of the boundary line - is 13 cm. Oblique diameter(diameter obliqua) of the entrance to the small pelvis is 12 cm. It is measured between the sacroiliac joint of one side of the pelvis and the ilio-pubic elevation of the other side.

The pelvic bones, sacrum, tailbone and their ligaments form the pelvis (pelvis). Its upper section is a large pelvis (pelvis major) wide, is part abdominal cavity, from the sides it is limited by the wings of the iliac bones, from the back - by the V lumbar vertebra and the lumbar-iliac ligament, the anterior wall is formed by muscles (Fig. 37). Downward, the large pelvis passes into the small pelvis (pelvis minor). The plane separating them, called the upper aperture of the small pelvis, is limited by the protrusion of the sacrum, the arcuate line of the ilium, the crest of the pubic bone and the upper edge of the pubic symphysis. The walls of the small pelvis are: in front - the symphysis, behind - the sacrum and coccyx, from the sides - the pelvic bones and their ligaments. The lower aperture of the small pelvis, or its outlet, is limited by the coccyx, the sacro-tubercular ligament, the sciatic tubercle, the branches of the sciatic and pubic bones and the lower edge of the symphysis.

Like other bone cavities, the pelvis protects the internal organs(rectum, bladder, in women - the ovaries, fallopian tubes, uterus, vagina, and in men - the prostate gland and seminal vesicles). The mechanical significance of the bone ring of the pelvis is great. The severity of the head and trunk is transmitted through the sacrum and pelvic bones to the lower extremities. In this case, the sacrum and pelvic bones act as a solid arch. In addition to this, the bone pelvis is directly related to one of the most important functions of the body - childbirth. Therefore, there are significant differences in the structure of the pelvis of men and women.

Sex differences in the structure of the pelvis (Fig. 38; see Fig. 37). The female pelvis is lower and wider, and the male pelvis is higher and narrower. The wings of the ilium in women are turned to the sides, and in men they are more vertical. In men, the pelvic cavity narrows downward. In the area of ​​the upper aperture, the promontory of the sacrum protrudes sharply forward, the cavity of the small pelvis narrows by closely spaced ischial spines and tubercles, the symphysis is narrow, high, the exit from the small pelvis is also limited by the protruding coccyx. In general, the pelvic cavity in men seems to be compressed from the sides. In the female pelvis, on the contrary, the entrance to the small pelvis looks like a smooth transverse oval, the promontory of the sacrum does not protrude, the sciatic tubercles are further apart, the symphysis is low, wide, the sacrum is flat, the tailbone protrudes not sharply into the lumen of the exit from the small pelvis. In general, the pelvis looks like a wide cylinder. The lower branches of the pubic bones in women form a wide arc, and in men - an acute angle. During pregnancy, the fibrous cartilage of the interpubic disc looses, the cartilage itself and the cavity in it increase, the symphysis becomes wider, which further increases the internal cavity of the small pelvis. Many bony points of the pelvis can be felt on a living person (iliac crests, upper anterior iliac spines, symphysis, ischial tubercles, etc.). This makes it possible to obtain important obstetric practice the size of the large and small pelvis. They are determined with a special obstetric compass-pelvimeter.

The size of the large pelvis of a woman (Fig. 39). The spinous distance (distantia spinarum) is 25 - 27 cm. To determine it, the legs of the compass are placed on the upper anterior spines of the ilium.

The crestal distance (distantia cristarum) is 28 - 29 cm. The legs of the compass are located at the most distant points of the iliac crests.

The trochanteric distance (distantia trochanterica) is 30 - 32 cm. This is the distance between the large trochanters of the femur.

The size of the small pelvis of a woman (Fig. 40). The anteroposterior dimensions in the pelvic area of ​​a woman are called straight dimensions or conjugates.

The external conjugate, or external straight size, is 21 cm. To determine it, one leg of the compass is placed on the skin in the region of the upper edge of the pubic symphysis, and the other on the skin in the fossa between the last lumbar and I sacral vertebra.

A very important true, or obstetric, conjugata vera. It characterizes the smallest direct size of the entrance to the small pelvis: between the promontory of the sacrum and the point of the pubic symphysis most protruding posteriorly. On average, the true conjugate is 10.5 - 11.0 cm. It can be determined in two ways. The first method consists in subtracting 10 cm from the value of the external straight size (21 cm). The second method involves a vaginal examination. In this case, the distance between the promontory of the sacrum and the lower edge of the pubic symphysis is determined. From the resulting figure (12.5 - 13.0 cm), subtract 2 cm.

The direct size of the exit from the small pelvis is on average 10 cm.

To determine it, one leg of the compass is placed on the skin in the coccyx region, and the other on the lower edge of the symphysis. Subtract 2 cm from the resulting figure (12 cm).

The transverse size of the entrance is 13.5 - 15.0 cm. It is found indirectly: the value of the ridge distance is divided in half.

The transverse size of the exit from the small pelvis is 11 cm (see Fig. 38). The legs of the compass are placed on the inner edges of the ischial tubercles. To the resulting figure (9 - 10 cm) add 1.0 - 1.5 cm (correction for the thickness of soft tissues).

1. TOPIC OF THE LESSON: PELVIS FROM THE OBSTETRIC POINT OF VIEW: THE SIZES OF THE LARGE PELVIS, THE SMALL PELVIS, ITS FLATS AND SIZES. FRUIT AS AN OBJECT OF LABOR: FRUIT HEAD, SKULL BONES, SEAMS AND SPRINGS. SIZES OF THE HEAD OF RETIRED FRUIT. POSITION OF THE FRUIT IN THE UTERINE.

2. Form of organization of the educational process: a practical lesson.

3. The meaning of the topic(relevance of the problem under study): Knowledge of anatomical structures, sizes normal pelvis, a medium-sized fetus is necessary for the further study of obstetrics.

4. Learning objectives:

4.1. common goal: study of the anatomy of the pelvis and structural features of the fetus; obstetric terminology.

4.2. Learning goal: the student must know the structure of the woman's pelvis and the fetal head; take measurements of the pelvis and fetal head, as well as timely diagnose abnormalities in the structure and size of the pelvis.

4.3. Psychological and pedagogical goal: Knowledge of the anatomical features of the structure of the bone pelvis, allows the doctor to determine the tactics of pregnancy and childbirth.

The student should know:

the structure of the bone pelvis;

planes of the small pelvis, their boundaries and sizes, diagonal, anatomical and true conjugates;

wire axis and angle of inclination of the pelvis;

muscles and fascia pelvic floor;

the structure of the skull of a full-term fetus, sutures, fontanelles and the size of the head, shoulder and pelvic girdle of the fetus;

basic obstetric terms (articulation, position, fetal axis, presentation, position and type);

signs of pregnancy (doubtful, probable, reliable), methods for diagnosing pregnancy, hormonal tests.

The student should be able to:

to show on the dummy of the female pelvis the boundaries of the planes of the small pelvis, the identification points of the anatomical and true conjugates;

four ways to identify with vera;

show the stitches and fontanelles on the head of a full-term fetus (doll);

the size of the head of a full-term fetus, signs of maturity;

on the phantom, give the doll a certain position, position, appearance, presentation;

determine the gestational age by various methods.

5. Place of the practical lesson: department of pathology of pregnancy, maternity department, study room, methodical office.

6. Equipment of the lesson:

1. Tables

2. A set of tickets to control the initial level of students' knowledge.

3. A set of tickets to control the final knowledge of students.

4. Obstetric simulator with a doll.

5. Dummy of the bone pelvis.

6. Dummy "Doll".

7. Tazometer, measuring tape.

8. Obstetric stethoscope.

8. Annotation of the topic(summary)

Of great importance in obstetrics is the bone pelvis, which is solid foundation birth canal. The pelvic floor, stretching, is included in the birth canal and contributes to the birth of the fetus.

Female pelvis (bone pelvis)

Bone pelvis is a strong receptacle for the internal genital organs of a woman, rectum, Bladder and surrounding tissues. The woman's pelvis forms the birth canal through which the fetus is being born. The development and structure of the pelvis has great importance in obstetrics.

The pelvis of a newborn girl differs sharply from the pelvis of an adult woman, not only in size, but also in shape. The sacrum is straight and narrow, located vertically, the cape is almost absent, its area is located above the plane of the entrance to the pelvis. The entrance to the small pelvis has an oval shape. The wings of the ilium are steep, the pelvis narrows significantly towards the exit. As the body develops, the volume and shape of the pelvis changes. The development of the pelvis, like the whole organism as a whole, is determined by environmental conditions and hereditary factors... The formation of the pelvis in childhood is particularly influenced by the effects associated with sitting, standing, walking. When the child begins to sit, the pressure from the torso is transmitted to the pelvis through the spinal column. When standing and walking, pressure from the lower extremities is added to the pressure on the pelvis from above. Under the influence of pressure from above, the sacrum moves somewhat into the pelvis. There is a gradual increase in the pelvis in the transverse direction and a relative decrease in the anteroposterior size. In addition, the sacrum, under the influence of pressure from above, rotates around its horizontal axis so that the cape drops and begins to protrude into the entrance to the pelvis. In this regard, the entrance to the pelvis gradually acquires the shape of a transverse oval with a notch in the area of ​​the cape. When turning the sacrum around the horizontal axis, its apex should have moved backward, but it is held by the tension of the sacrospinous and sacro-tuberous ligaments. As a result of the interaction of these forces, a bend of the sacrum (sacral cavity) is formed, typical for the pelvis of an adult woman.

Differences between the female pelvis and the male begin to come to light during puberty and become distinct in adulthood:

1.the bones of the female pelvis are thinner, smoother and less massive than the bones of the male pelvis;

2. the female pelvis is lower, wider and larger in volume;

3. the sacrum in women is wider and not as strongly concave as in the male pelvis;

4. the sacral promontory in women protrudes forward less than in men;

5. the symphysis of the female pelvis is shorter and wider;

6. the entrance to the small pelvis in a woman is more extensive, the shape of the entrance is transverse-oval, with a notch in the area of ​​the cape; the entrance to the male pelvis resembles a card heart due to the sharper protrusion of the cape;

7. the cavity of the small pelvis in women is more extensive, in its outlines it approaches the cylinder, curved anteriorly; the cavity of the male pelvis is smaller, it narrows in a funnel-like manner downward;

8. the outlet of the female pelvis is wider because the distance between the ischial tubercles is greater, the pubic angle is wider (90-100 0) than in men (70-75 0); the tailbone protrudes less anteriorly than in the male pelvis.

Thus, the female pelvis is more voluminous and wider, but less deep than the male pelvis. These features are important for the childbirth process.

The development of the pelvis can be disrupted under unfavorable conditions of intrauterine development associated with diseases, malnutrition and other disorders in the mother's body. Severe debilitating diseases, unfavorable living conditions in childhood and during puberty can lead to a delay in pelvic development. V similar cases traits typical of the child's and youthful pelvis may persist until the woman's puberty.

BONES PELVIS

The pelvis consists of four bones: two pelvic (or nameless) bones, the sacrum and the coccyx.

Pelvic (nameless) bone(os coxae, os innominatum) up to 16-18 years old consists of three bones connected by cartilage: iliac, pubic and sciatic. After ossification of the cartilage, these bones grow together to form the nameless bone.

Ilium(os ilium) consists of two parts: the body and the wing. The body makes up the short, thickened part of the ilium and participates in the formation of the acetabulum. The wing of the ilium is a rather wide plate with a concave inner and convex outer surface. The most thickened free upper edge of the wing forms iliac crest(crista iliaca). In front, the ridge begins with a ledge ( anterosuperior spine- spina iliaca anterior superior), below is the second protrusion (the lower spine - spina iliaca anterior inferior). Under the anteroinferior axis, at the junction with the pubic bone, there is a third eminence - ilio-pubic tubercle(tuberculum iliopubicum). Between the anteroposterior and antero-inferior iliac spine there is a small iliac notch, between the antero-inferior spine and the iliac-pubic tubercle there is a large iliac notch. The posterior iliac crest ends posterosuperior iliac spine(spina iliaca posterior superior), below which the second protrusion is located - the posterior iliac spine (spina iliasa posterior inferior). Under the posterior spine is a large sciatic notch (incisura ischiadica major). On inner surface the ilium, in the region of the transition of the wing into the body, there is a ridge-like protrusion, which forms an arcuate borderline, or nameless line (linea terminalis, s innominata). This line runs from the sacrum across the entire ilium, in front of it passes to the upper edge of the pubic bone.

Ischium(os ischii) has a body involved in the formation of the acetabulum, and two branches: upper and lower. The upper branch goes down from the body and ends sciatic tubercle(tuber ischiadicum). There is a ledge on the back surface of the lower branch - sciatic spine(spina ischiadica). The lower branch is directed anteriorly and upward and connects to the lower branch of the pubic bone.

Pubic bone, or pubic (os pubis), forms the anterior wall of the pelvis. The pubic bone consists of a body and two branches: upper (horizontal) and lower (descending). The short body of the pubic bone is part of the acetabulum, the lower branch is connected to the corresponding branch of the ischium. On the upper edge of the upper (horizontal) branch of the pubic bone, there is a sharp ridge, which ends in front of the pubic tubercle (tuberculm pubicum). The upper and lower branches of both pubic bones in front are connected to each other by means of an inactive pubic articulation (connection) - symphysis(symphisis). Both pubic bones are connected in the symphysis by an intermediate cartilage, in which there is often a small slit cavity filled with fluid; during pregnancy, this gap increases. The lower branches of the pubic bones form an angle under the symphysis, which is called the pubic arch. The connecting branches of the pubic and ischial bones limit a rather extensive obturator opening (foramen obturatorium).

Sacrum(os sacrum) consists of five accrete vertebrae. The size of the sacral vertebrae decreases downward, so the sacrum has the shape of a truncated cone. Its wide part - the base of the sacrum - faces upwards, the narrow part - the apex of the sacrum - downwards. The posterior surface of the sacrum is convex, the anterior surface is concave, it forms a sacral cavity. On the anterior surface of the sacrum (in the cavity), four rough transverse lines are visible, corresponding to the ossified cartilaginous joints of the sacral vertebrae. The base of the sacrum (surface of the I sacral vertebra) articulates with the V lumbar vertebra; a protrusion forms in the middle of the anterior surface of the base of the sacrum - sacral promontory(promontorium). Between the spinous process of the V lumbar vertebra and the beginning of the middle sacral ridge, it is possible to probe the cavity ( supra-sacral fossa), which is used when measuring the pelvis.

Coccyx(os coccygis) consists of 4-5 fused vertebrae, is a small bone, tapering downward.

The pelvic bones are connected through the symphysis, sacroiliac and sacrococcygeal joints. Cartilaginous layers are located in the joints of the pelvis. The joints of the pelvis are reinforced with strong ligaments. Symphysis is a sedentary joint, half-joint.

There are two parts of the pelvis: the upper - the large pelvis - and the lower - the small pelvis. The boundaries between the large and small pelvis are: in front - the upper edge of the symphysis and pubic bones, on the sides - unnamed lines, behind - the sacral promontory. The plane lying between the large and small pelvis is the plane of entry into the small pelvis, this plane is of paramount importance in obstetrics.

LARGE BOWL

The large pelvis is much wider than the small one, it is bounded from the sides by the wings of the ilium, from the back by the last lumbar vertebrae, and from the front by the lower part of the abdominal wall. The volume of the large pelvis can change in accordance with the contraction or relaxation of the abdominal muscles. A large pelvis is available for examination, its dimensions are determined and quite accurately. The size of the large pelvis is used to judge the size of the small pelvis, which is inaccessible to direct measurement. Determination of the size of the small pelvis has essential, since the fetus passes through the stubborn bone canal of the small pelvis.

Usually four sizes of the pelvis are measured: three transverse and one straight.

1.Distantia spinarum (24-26 cm)

2. Distantia cristarum (27-29 cm)

3. Distantia trochanterica (30-31 cm)

4. Conjugata externa (20-21 cm)

By the size of the outer conjugate, one can judge the size of the true conjugate: 9 cm is subtracted from the outer length. The sacral rhombus (Michaelis rhombus) is also examined and measured.

SMALL BOWL

Determining the size of the small pelvis is important, because the fetus passes through the stubborn bone canal of the small pelvis. The small basin has: an entrance, a cavity and an exit. In the pelvic cavity, a wide and narrow parts are distinguished.

Planes and dimensions of the small pelvis... The small pelvis is the bony part of the birth canal. The posterior wall of the small pelvis consists of the sacrum and coccyx, the lateral ones are formed by the ischial bones, the anterior one - by the pubic bones and symphysis. The posterior wall of the small pelvis is 3 times longer than the anterior one. The upper part of the small pelvis is a solid, unyielding bone ring. In the lower part, the walls of the small pelvis are not solid; they have obturator openings and ischial notches, limited by two pairs of ligaments (sacrospinous and sacro-tuberous).

In the small pelvis, there are the following sections: entrance, cavity and exit. In the pelvic cavity, a wide and narrow part is distinguished. In accordance with this, four planes of the small pelvis are considered: I - the plane of the entrance to the pelvis, II - the plane of the wide part of the pelvic cavity, III - the plane of the narrow part of the pelvic cavity, IV - the plane of the exit of the pelvis.

I. The plane of the entrance to the small pelvis has the following boundaries: in front - the upper edge of the symphysis and the upper inner edge of the pubic bones, on the sides - unnamed lines, behind - the sacral promontory. The plane of the entrance has the shape of a kidney or a transverse oval with a notch corresponding to the sacral promontory. Three sizes are distinguished at the entrance to the pelvis: straight, transverse and two oblique.

Straight size- the distance from the sacral promontory to the most prominent point on the inner surface of the pubic articulation. This size is called obstetric, or true, conjugate (conjugata vera). There is also an anatomical conjugate - the distance from the cape to the middle of the upper inner edge of the symphysis; the anatomical conjugate is slightly (0.3-0.5 cm) larger than the obstetric conjugate. Obstetric, or true conjugate is 11 cm.

Transverse dimension- the distance between the most distant points of the unnamed lines. This size is 13-13.5 cm.

Oblique dimensions two: right and left, which are 12-12.5 cm. Right oblique size - the distance from the right sacroiliac joint to the left iliac-pubic tubercle, the left oblique size - from the left sacroiliac joint to the right iliac-pubic tubercle. In order to make it easier to navigate in the direction of the oblique dimensions of the pelvis in a woman in labor, M.S. Malinovsky and M.G. Kushnir offer the following trick. The brushes of both hands are folded at right angles, with the palms facing up; the ends of the fingers are brought closer to the outlet of the pelvis of the lying woman. The plane of the left hand will coincide with the left oblique size of the pelvis, the plane of the right - with the right.

II. The plane of the wide part of the pelvic cavity has the following boundaries: in front - the middle of the inner surface of the symphysis, on the sides - the middle of the acetabulum, behind - the junction of the II and III sacral vertebrae. In the wide part of the pelvic cavity, two sizes are distinguished: straight and transverse.

Straight size- from the junction of the II and III sacral vertebrae to the middle of the inner surface of the symphysis; is equal to 12.5 cm.

Transverse dimension- between the tops of the acetabulum; is equal to 12.5 cm.

There are no oblique dimensions in the wide part of the pelvic cavity because in this place the pelvis does not form a continuous bone ring. Oblique dimensions in the wide part of the pelvis are allowed conditionally (length 13 cm).

III. The plane of the narrow part of the pelvic cavity bounded in front by the lower edge of the symphysis, from the sides - by the spines of the ischial bones, behind - by the sacrococcygeal joint. There are two sizes: straight and transverse.

Straight size goes from the sacrococcygeal joint to the lower edge of the symphysis (the top of the pubic arch); equal to 11-11.5 cm.

Transverse dimension connects the spine of the ischial bones; is equal to 10.5 cm.

IV. Exit plane of the small pelvis has the following boundaries: in front - the lower edge of the symphysis, from the sides - ischial tubercles, behind - the apex of the coccyx. The exit plane of the pelvis consists of two triangular planes, the common base of which is the line connecting the ischial tubercles. At the outlet of the pelvis, two sizes are distinguished: straight and transverse.

Straight size of the pelvic outlet goes from the top of the coccyx to the lower edge of the symphysis; it is equal to 9.5 cm.When the fetus passes through the small pelvis, the tailbone departs by 1.5-2 cm and the straight size increases to 11.5 cm.

Transverse size of the pelvic outlet connects the inner surfaces of the ischial tuberosities; is 11 cm. Thus, at the entrance to the small pelvis, the transverse dimension is the largest. In the wide part of the cavity, the straight and transverse dimensions are equal; the largest size will be the conventionally accepted oblique size. In the narrow part of the cavity and the outlet of the pelvis, the straight dimensions are larger than the transverse ones.

Wire axis (line) of the pelvis. All planes (classical) of the small pelvis in front are bordered by one or another point of the symphysis, and behind - with different points of the sacrum or coccyx. The symphysis is much shorter than the sacrum with the coccyx, so the planes of the pelvis converge anteriorly and fan out posteriorly. If you connect the middle of the straight dimensions of all the planes of the pelvis, you get not a straight line, but a concave anteriorly (to the symphysis) line. This conditional line, connecting the centers of all the straight sizes of the pelvis, is called the wired axis of the pelvis. The hard axis of the pelvis is straight at first, it bends in the pelvic cavity according to the concavity of the inner surface of the sacrum. In the direction of the wired axis of the pelvis, the newly born fetus passes through the birth canal.

The angle of inclination of the pelvis (the intersection of the plane of its entrance with the plane of the horizon) when a woman is standing can be different depending on the physique and ranges from 45-55 0. It can be reduced by forcing the woman, lying on her back, to pull her thighs strongly against the abdomen, which leads to a lifting of the bosom. It can be increased by placing a roller-like rigid pillow under the lower back, which will lead to a deviation of the bosom downward. A decrease in the angle of inclination of the pelvis is also achieved if the woman is given a semi-sitting position, squatting.

Pelvic floor

The exit of the pelvis is closed from below by a powerful muscle-fascial layer, which is called the pelvic floor. The part of the pelvic floor, located between the posterior commissure of the labia and the anus, is called the obstetric or anterior, perineum (the posterior perineum is the part of the pelvic floor located between the anus and the coccyx).

The pelvic floor is made up of three layers of muscle clad with fascia:

I. Bottom (outer) layer consists of muscles converging in the tendon center of the perineum; the shape of the location of these muscles resembles a figure eight, suspended from the bones of the pelvis.

1. Bulbous-cavernous muscle(m.bulbo-cavernosus) grabs the vaginal opening, attaches to the tendon center and clitoris; when contracted, this muscle compresses the vaginal opening.

2. The sciatic-cavernous muscle(m.ischio-cavernosis) starts from the lower branch of the ischium and is attached to the clitoris.

3. Superficial transverse muscle of the perineum(m.transversus perinei superficialis) starts from the tendon center, goes to the right and left, attaches to the ischial tubercles.

4. External press of the anus(m.sphincter ani externus) - the muscle surrounding the end of the rectum. Deep bundles of muscles of the external sphincter of the anus begin the apex of the coccyx, encircle the anus and end in the tendon center of the perineum.

II. Middle layer of the pelvic muscles- the urogenital diaphragm (diaphragma urogenitale) occupies the anterior half of the pelvic outlet. The urogenital diaphragm is a triangular muscle-fascial plate located under the symphysis, in the pubic arch. The urethra and vagina pass through this plate. In the anterior part of the urogenital diaphragm, muscle bundles surround the urethra and form its external sphincter; in the posterior section, muscle bundles are laid, going in the transverse direction to the ischial tubercles. This part of the urogenital diaphragm is called the deep transverse perineal muscle. (m.transversus perinei profundus).

III. Upper (inner) the layer of muscles in the perineum is called the diaphragma pelvis. The pelvic diaphragm consists of a paired muscle that lifts the anus (m.levator ani). Both broad levators of the anus form a dome with the apex facing downward and attached to the lower rectum (slightly above the anus). The wide base of the dome faces upward and is attached to the inner surface of the pelvic walls. In the anterior part of the pelvic diaphragm, between the muscle bundles that raise the anus, there is a longitudinally located gap through which the urethra and vagina (hiatus genitalis) exit the pelvis. The muscles that lift the anus are composed of separate muscle bundles starting from different parts of the pelvic walls; this layer of the pelvic muscles is the most powerful. All pelvic floor muscles are covered with fascia.

In childbirth, the perineum is often injured, and it is the inner layer of the pelvic floor that is damaged.

The muscles and fascia of the pelvic floor perform the following critical functions:

1. The pelvic floor is a support for the internal genital organs, helps to maintain their normal position. The muscles that lift the anus are of particular importance. With the contraction of these muscles, the genital gap closes, the lumen of the rectum and vagina narrows. Damage to the pelvic floor muscles leads to prolapse and prolapse of the genitals.

2. The pelvic floor is a support not only for the genitals, but also for the viscera. The pelvic floor muscles are involved in the regulation of intra-abdominal pressure together with the abdominal obstruction and the muscles of the abdominal wall.

3. During childbirth, when the fetus is expelled, all three layers of the pelvic floor muscles are stretched and form a wide tube, which is a continuation of the bony birth canal. After the birth of the fetus, the pelvic floor muscles contract again and return to their previous position.

The pelvis as a whole It is subdivided into large and small along the border through the sacral promontory (formed by the anterior part of the base of the sacrum and the body of the Y lumbar vertebra), through the arcuate lines of the iliac bones, the crests of the pubic bones and the upper edge of the pubic symphysis - the entire border is called the border line. The pelvic cavity is occupied by internal organs and muscles, from below it is limited by the pelvic and urogenital diaphragms. The muscles of the lower girdle are located outside the pelvis.

V small pelvis distinguish: the upper aperture (entrance), the cavity with wide and narrow parts, the lower aperture (exit). The upper aperture coincides with the border line, the lower one passes from behind through the apex of the coccyx, on the sides - through the sacro-tuberous ligaments, ischial tubercles, sciatic branches, in front - along the edge of the lower pubic branches and the lower edge of the pubic symphysis. On the front wall of the small pelvis there are obturator openings with the same canals, on the side walls there are large and small sciatic openings, bounded by the same bony notches and sacro-tuberous, sacrospinous ligaments.

Age differences in the structure of the pelvis are determined by changes in the angle of inclination and the degree of curvature of the sacrum and coccyx. Individual fluctuations in the angle of inclination of the pelvis (in men - in the range of 50-55 o, in women - 55-60 o) vary depending not only on gender, but also on the position of the body. In a sports or military stance, the angle of inclination increases as much as possible, in a sitting position it decreases as much as possible. Significant age-related fluctuations are also observed in terms of ossification of the pelvic ring bones.

Sex differences are manifested in the following:

• female pelvis, and especially its cavity, wide and low, with a cylindrical shape; male - narrow and tall with a conical cavity;

· The cape in women weakly protrudes into the cavity, forming an entrance in the form of an oval; the cape in men protrudes strongly, forming an entrance in the form of a card heart;

• the female sacrum is wide and short with a slightly concave, almost flat pelvic surface; male - narrow and long, strongly curved along the pelvic surface;

· Sub-pubic angle in women - more than 90 degrees, in men - 70-75 degrees;

· The wings of the iliac bones in women are more turned outward, and in men they have a more vertical position;

· The linear dimensions of the female pelvis prevail over those of men.

In the large pelvis in women, three transverse and one longitudinal size are distinguished:

· Interspinous size, as a direct distance of 23-25 ​​cm between the anterior superior spines of the iliac bones;

· Inter-crestal size, as a straight distance of 26-28 cm between the most distant points of the iliac crests;

· Intertrochanteric dimension, as a direct distance of 30-33 cm between the most distant points of the greater trochanters;

· Longitudinal size, as a straight distance of 18-21 cm between the spinous process of the Y lumbar vertebra and the upper edge of the pubic symphysis.

All sizes of the large pelvis are measured with a thick compass in a living woman, since these bone formations are easily palpable. By the size of the large pelvis and its shape, one can indirectly judge the shape of the small pelvis.

In the small pelvis, there are transverse, oblique, longitudinal dimensions (diameters), which in each part of the pelvis (upper, lower apertures, cavity) are also measured between certain bony landmarks. So, for example, the transverse diameter of the entrance is the distance of 12-13 cm between the most spaced points of the arcuate line on the ilium; oblique diameter - 12 cm distance between the sacroiliac joint of one side and the ilio-pubic eminence opposite side; straight size 11 cm, as the distance between the cape and the point of the pubic symphysis most protruding posteriorly. The straight outlet size of 9 cm is the distance between the apex of the coccyx and the lower edge of the pubic symphysis; the transverse size of the exit is 11 cm - the distance between the ischial tubercles. If you connect the midpoints of all straight dimensions, you get the wired axis of the small pelvis - a gentle curve, concavity facing the symphysis. This is the direction of movement of a child being born.

Hip joint.

The hip joint is formed by the acetabulum pelvic bone and the femoral head. To increase the articular surface along the edge of the acetabulum, there is a fibrous-cartilaginous acetabular lip with a transverse acetabular ligament. The articular capsule, consisting of fibrous and synovial membranes, is attached along the edge of the acetabular lip, and on femur along the neck: in front - along the intertrochanteric line, behind - inward from the intertrochanteric ridge. The capsule is strengthened by powerful ligaments: the circular zone, the ilio-femoral, pubic and sciatic-femoral ligaments. A ligament of the femoral head is located inside the joint, which during its formation holds the head in the cavity.

The hip joint in shape refers to the spherical, triaxial, appearing as a kind of these joints - the cup-shaped joint. Around the frontal axis, flexion is performed in it with a bent knee at 118-121 o, with an unbent one - only at 84-87 o due to tension back muscles hips. Flexion is carried out by the muscles: iliopsoas, rectus femur, tailor, comb, fascia lata tensor. They are supplied with blood by the following arteries: the ilio-lumbar, superior gluteal, obturator, external genital, deep and lateral surrounding the ilium, the descending knee, muscle branches of the femoral and deep femoral arteries. Innervation is carried out by the branches of the lumbar plexus, obturator, femoral and superior gluteal nerves

Knee-joint.

In education knee joint three bones are involved: the femur with the articular condylar surfaces, the patella with the posterior articular surface, the tibial with the upper articular surfaces on the medial and lateral condyles. Therefore, the joint is complex and condylar with insufficient correspondence of the articulating surfaces, which is complemented by fibrocartilaginous menisci: medial and lateral. From this, the joint becomes complex.

The medial meniscus is narrow, lunar (in the form of the letter " WITH"); lateral meniscus - wide, oval (in the form of the letter " O"). In front, both menisci are connected by the transverse ligament of the knee, inside they grow to the intercondylar elevation of the tibia. A thin and loose capsule grows together with the outer edges of the menisci, its synovial membrane forms large pterygoid and numerous, small folds filled with adipose tissue, which increases the congruence of the articular surfaces. Paired pterygoid folds lie laterally and downward from the patella. The patellar fold - unpaired is located below the patella, located between it and the anterior intercondylar field.

The synovium in the joint forms pockets (sinuses, twists), the size and number of which is variable. Synovial bursae occur at the attachment points of muscle tendons: suprapatellar (the most extensive), subpatellar deep, hamstring pocket (behind - at the tendon of the muscle of the same name), bag of the sartorius muscle tendon, subcutaneous prepatellar bursa. Some bursae, connecting with the joint cavity, increase its volume.

The joint capsule is reinforced with internal and external ligaments. The internal ligaments include cruciate ligaments: anterior and posterior, filling the intercondylar fossa of the femur and the intercondylar field of the tibia. The extra-articular, external ligaments include: the collateral patellar and peroneal ligaments lying on the sides, the oblique popliteal and arcuate popliteal in the back, the patellar ligament (patellar) in the front, and the medial and lateral patellar support ligaments.

The knee joint is a typical condylar joint, complex and complex, in which the following movements are performed:

· Around the frontal axis: flexion and extension with a span of 140-150 o; flexion is inhibited by the cruciate ligaments and the quadriceps tendon; the condyles of the femur slide along the menisci;

· Around the longitudinal (vertical) axis, the volume of active rotation is on average 15 °, passive - 30-35 °; inward rotation is limited by cruciate ligaments, outward - by collateral ligaments.

The joints of the shin bones.

Tibia

The distal pineal gland has:

Fibula It has:

The shin bones have connections:

· tibiofibular joint formed by the flat articular surfaces of the peroneal head and upper epiphysis (lateral part), tibia; the articular capsule is tightly stretched and strengthened by the anterior and posterior ligaments of the fibular head; limited range of motion; sometimes the tibiofibular joint can communicate with the cavity of the knee joint;

· tibiofibular syndesmosis- continuous connection by short and thick fibrous fibers between the peroneal notch on the distal epiphysis of the tibia and the articular surface of the lateral ankle, strengthened by the anterior and posterior tibiofibular ligaments, the synovial membrane of the ankle joint invades the tibiofibular syndesmosis;

· interosseous membrane of the lower leg- a fibrous membrane stretched between the interosseous edges of the greater and fibular bones in the area of ​​their diaphysis; it has holes at the top and bottom for the passage of blood vessels and nerves.

In the joints of the lower leg bones, movements are almost absent, which is associated with support function lower limbs and the formation of a movable ankle joint.

· tibia

· fibula

· talus

Tibia on the proximal pineal gland has:

· Medial and lateral condyles with articular surfaces;

· Intercondylar eminence with medial and lateral tubercles :, anterior and posterior fields;

· The peroneal articular surface from the lateral side below the condyle.

On the diaphysis of the tibia are located:

· The anterior edge (acute) - upward passes into tuberosity, the lateral edge facing the fibula and the medial edge;

· Surfaces: medial, lateral and posterior with the soleus muscle line.

The distal pineal gland has:

· Peroneal notch along the lateral edge;

· The medial malleolus with the ankle groove at the back;

· Articular surfaces: ankle and lower.

The ossification nuclei in the tibia appear in the proximal epiphysis at the end of the fetal period, in the distal - at the 2nd year of life, in the diaphysis - at the beginning of the fetal period. The final ossification occurs at the age of 19-24, the ankles at the age of 16-19.

Fibula It has:

· On the proximal epiphysis, the head, neck, on the head - the apex and articular surface;

On the diaphysis: anterior, posterior and interosseous edges; lateral, posterior and medial surfaces;

· On the distal epiphysis: the lateral malleolus with the articular surface and the fossa (behind).

Secondary nuclei of ossification appear in the distal epiphysis at the 2nd year of life, in the proximal at 3-5 years, the final ossification at 20-24 years.

Ankle joint.

The formation of the joint involves:

· The tibia with its lower and medial ankle articular surfaces;

· The fibula with the articular surface of the lateral malleolus;

· Talus of the upper and ankle (medial and lateral) articular surfaces located on the block;

· The ankles sweep the block like a pitchfork, forming a typical block joint - complex due to the articulation of three bones.

The articular capsule is attached from the back along the edge of the articular surfaces of the bones that make up the joint, in front by 0.5-1 cm above it.

On the sides, the capsule is thick and strong, in front and behind it is thin, loose, folded; reinforced by lateral ligaments:

· medial(deltoid) - thick, strong, fanning out from the medial malleolus to the talus, scaphoid and heel bones; in the ligament, parts are distinguished: tibial-scaphoid, tibial-calcaneal, anterior and posterior tibial-talus;

· lateral as part of the anterior talofibular, posterior talofibular, calcaneofibular ligaments.

The ligaments are so strong, especially the medial, that, with maximum stretching, they can tear off the ankle.

In the ankle and talocalcaneonavicular joints, the following movements are performed:

· flexion(plantar) and extension (sometimes called dorsiflexion) around the frontal axis with a span of 60 degrees;

· adduction and abduction around the sagittal axis with a span of 17 degrees;

· pronation and supination around the vertical axis with a span of 22 degrees.

The joint of the foot.

Foot bones subdivided into tarsal bones: 7 short cancellous bones and metatarsal bones consisting of 5 short tubular bones; and also the phalanges of the fingers - three in each finger, except for the first, which has two phalanges. The bones of the tarsus lie in two rows: in the proximal (posterior) - the talus and calcaneal, in the distal (anterior) - scaphoid, wedge-shaped: medial, intermediate, lateral and cuboid bones.

Talus consists of a body, head, neck. On top of the body there is a block with the superior, medial and lateral ankle articular surfaces. Below on the body are the calcaneal articular surfaces: anterior, middle and posterior. Between the middle and posterior calcaneal surfaces is the talus groove. The scaphoid articular surface lies on the head. The talus has processes: lateral and posterior, on the latter - the medial and lateral tubercles, separated by a groove for the tendon of the long flexor of the thumb.

Heel bone has a body ending posteriorly with a calcaneal tubercle. On the body, the talus articular surfaces are distinguished: anterior, middle and posterior. Between the middle and the back is the groove of the calcaneus, which, together with the groove of the talus, forms the tarsal sinus. At the distal end of the body there is a cuboid articular surface. The processes and other grooves of the calcaneus are the supporting process of the talus on the medial surface, the groove of the tendon of the long peroneal muscle on the lateral surface.

Scaphoid at the distal end it has three articular surfaces for the sphenoid bones, tuberosity along the medial edge for attaching the posterior tibial muscle.

Sphenoid bones have a characteristic triangular shape, and on the front and back sides and on the sides - articular surfaces - in front for articulation with the first three metatarsal bones, behind for connection with the scaphoid bone, on the sides for articulation with each other and the cuboid bone.

Cuboid also has articular surfaces behind for articulation with the calcaneus, in front - with the metacarpal bones, and along the medial surface - for connecting the lateral sphenoid and scaphoid bones. On the lower surface there is a tuberosity and a groove for the tendon of the peroneus longus muscle.

Metatarsal bones and phalanges- These are short tubular bones, each of which consists of a base, body and head. The articular surfaces are at the head and base. The head of the first metatarsal bone from below is divided into two platforms, with which the sesamoid bones are in contact. On the lateral surface of the Y metatarsal bone there is a tuberosity for the attachment of the short peroneal muscle. Each distal (nail) phalanx ends with a tubercle for the attachment of muscle tendons.

The primary ossification nuclei appear in the calcaneus at the 6th month of the fetal period, in the talus at 7-8, in the cuboid at the 9th month. In the remaining bones of the tarsus, secondary nuclei are formed: in the lateral wedge-shaped - at the 1st year, in the medial wedge-shaped - by 3-4, in the scaphoid - at 4-5 years, complete ossification - at 12-16 years.

Metatarsal bones begin to ossify in the epiphyses at 3-6 years old, complete ossification - at 12-16 years old. The diaphysis of the phalanges and metatarsal bones form the primary nuclei at 12-14 weeks of the fetal period, the secondary ones in the phalanges at 3-4 years, complete ossification of the phalanges at 18-20 years

The following are involved in the formation of the ankle joint:

· tibia its lower and medial ankle articular surfaces;

· fibula- the articular surface of the lateral ankle;

· talus- upper and ankle (medial and lateral articular surfaces) located on the block.

The ankles are forked around the block, forming a typical blocky joint, complex due to the articulation of three bones.

The articular capsule is attached from the back along the edge of the articular surfaces of the articulating bones, in front by 0.5-1 cm above it.

On the sides, the capsule is thick and strong, in front and behind it is thin, loose, folded, reinforced with powerful lateral ligaments:

· Medial (deltoid) - thick, strong, fanning out from the medial malleolus to the talus, scaphoid and heel bones; in the ligament, parts are distinguished: tibial-scaphoid, tibial-calcaneal, anterior and posterior tibial-talus;

· Lateral in the anterior talofibular, posterior talofibular, calcaneofibular ligaments.

The ligaments are so strong, especially the medial, that, with maximum stretching, they can tear off the ankle.

The following movements are performed in the ankle joint:

· flexion(plantar) and extension (dorsiflexion) around the frontal axis with a span of 60 about;

· adduction and abduction around the sagittal axis with a span of 17 about;

· pronation and supination around the vertical axis with a span of 22 about.

Subtalar joint formed by the posterior articular surfaces of the talus and calcaneus, which match well. The capsule at the joint is thin, stretched, reinforced with ankle ligaments.

Talocalcaneonavicular joint formed by the articular surface on the head of the talus, which articulates in front with the scaphoid bone, and below with the calcaneus. The articular surface of the calcaneus is complemented by the plantar calcaneonavicular ligament, which at the head of the talus passes into fibrous cartilage. The articular capsule is attached along the edge of the articular surfaces, closing a single cavity. The capsule is strengthened by strong ligaments: the interosseous talocalcaneal up to 0.5 cm thick and from above - the talo-navicular. When stretching them (especially the talocalcaneal ligament), the head of the talus is lowered and the foot is flattened.

The joint is spherical in shape, but with one sagittal axis of motion. Together with the subtalar joint, it forms a combined joint with a limited range of motion in the form of adduction and abduction, turning the foot outward and inward. The total volume of all movements does not exceed 55 o. In a newborn and infant this joint is in a supinated position, with the beginning of walking, pronation gradually occurs with the lowering of the medial edge of the foot.

Heel-cuboid joint- saddle with great congruence of articular surfaces; the joint capsule is thick and taut on the medial side, thin and loose on the lateral side, reinforced with ligaments: plantar calcaneal-cuboid and long plantar. Movements in a limited volume are carried out around the longitudinal axis in the form of a slight rotation, complementing the movements in the talocalcaneonavicular joint.

The transverse (Choparov) joint of the tarsus includes the calcaneo-cuboid and talo-navicular joints so that the joint space takes the form of the Latin S, passing across the foot. Common ligament of joints - bifurcated ( lig. bifurcatum) - serves as a kind of key, when dissected, the joint cavity opens wide. It has a Y-shaped appearance and consists of the calcaneonavicular and calcaneo-cuboid ligaments.

Wedge-navicular joint- flat, complex, as it is formed by three wedge-shaped and one navicular bones, reinforced by the dorsal and plantar wedge-navicular and intra-articular intercliniform ligaments. The joint cavity can communicate with the tarsometatarsal joints.

Tarsometatarsal (Lisfranc) joints- flat with limited range of motion, include the following three joints:

· The joint between the medial sphenoid and first metatarsal bones;

· The joint between the intermediate, lateral sphenoid bones and II, III metatarsal;

· The joint between the cuboid bone and IY, Y metatarsal bones;

· The tarsometatarsal joints are strengthened by the tarso-metatarsal ligaments (dorsal and plantar) and interosseous cuneiform ligaments, of which the medial cuneiform ligament is considered in practice to be the key of these joints.

Intermetatarsal joints- flat, formed by the lateral surfaces of the bases of the metatarsal bones, reinforced by the dorsal and plantar metatarsal interosseous ligaments. Movement in them is severely limited.

Metatarsophalangeal joints formed by the spherical heads of the metatarsal bones and the concave bases of the proximal phalanges. The capsules are thin, loose, reinforced with collateral and plantar ligaments. The deep transverse metatarsal ligament connects the metatarsal heads and strengthens the joint capsules. Flexion and extension in them is 90 o, adduction and abduction are limited.

Interphalangeal joints- proximal and distal, except for the thumb joint, where there is one interphalangeal joint. They belong to blocky joints, reinforced with collateral and plantar ligaments.

The human foot has lost the adaptations of the grasping organ, but has acquired the arches necessary for support and movement of the whole body.

The bones of the tarsus and metatarsal are connected by sedentary joints.

Moreover, due to the shape of the bones and their "tight" joints, five longitudinal and one transverse vaults were formed upwardly convex with points of support on the calcaneal tubercle and the heads of the I and Y metatarsal bones.

The longitudinal vaults run along the long axis of the metatarsal bones: from their heads, through the body to the base and further through the adjacent tarsal bones to the calcaneal tuberosity, where they all converge. The longest and highest is the second vault.

The medial longitudinal vaults perform the spring (springing) function, the lateral ones - the supporting one. At the level of the most high points the longitudinal vaults are transverse.

The vaults are held in place due to the shape of the bones and joints, reinforced with passive "puffs" - ligaments with the plantar aponeurosis and active "puffs" - muscles and their tendons. The longitudinal arches strengthen the following ligaments: long plantar, calcaneonavicular and plantar aponeurosis. The transverse arch is held by the metatarsal transverse and interosseous ligaments. The tendons of the long flexors and extensors of the fingers, the tibial muscles, as well as the short flexors of the fingers, the vermiform muscles strengthen the longitudinal arches. The transverse arch is held by the square sole of the sole, adductor and interosseous muscles.

In the course of human evolution, major changes occurred in the foot, associated with its vaulted structure. Three support points were formed on the sole - the heel and the bases of the first and fifth toes, the tarsal bones increased in size, and the phalanges of the toes were significantly shortened. The joints of the foot became stiff. Attachment of the long muscles of the leg and short muscles of the foot has shifted medially towards thumb, which strengthens the pronation of the foot and strengthens the arches. The loss of acquired properties is accompanied by the development of flat feet, which is a disease for humans.