Features of the structure and dimensions of the female pelvis. Structure of the human pelvis

It forms a generic the channel through which the fetus moves. Not favorable conditions intrauterine development, diseases transferred to childhood and inperiod of puberty, can lead to disruption of the structure and developmentpelvis The pelvis can be deformed as a result of injuries, tumors, various exostoses. Differences in the structure of the female and male pelvis begin to appear during puberty and become pronounced in mature age. Bones female pelvis thinner, smoother and less massive than the husband's bones pelvis. The plane of entrance to the pelvis in women has a transverse oval shape, while in men it has the shape of a card heart (due to the strong protrusion of the promontory).

Anatomically, the female pelvis is lower, wider and larger in volume. The pubic symphysis in the female pelvis is shorter than the male one. The sacrum in women is wider, the sacral cavity is moderately concave. The pelvic cavity in women in outline approaches a cylinder, and in men it narrows funnel-shaped downwards. The pubic angle is wider (90-100°) than in men (70-75°). The coccyx protrudes anteriorly less than in the male pelvis. The ischial bones in the female pelvis are parallel to each other, and in the male pelvis they converge.

All of the above features are very great importance during the birth act, Pelvis adult woman consists of 4 bones: two pelvic, one sacral and one coccygeal, firmly connected to each other,

Hip bone, or nameless (os coxae, os innominatum), consists of up to 16— 18 years old from 3 bones connected by cartilage in the acetabulum area(acetabulum): iliac (os ileum), sciatic (os ischii) and pubis (os pubis ). After puberty, the cartilages fuse together and a solid bone mass is formed - the pelvic bone.

On ilium differentiate upper section- wing and lower - body.At the place of their connection, an inflection is formed, called an arcuate or be-zimyanny line ( linea arcuata, innominata ). On the ilium should bemark a number of protrusions that have important for the obstetrician. The upper one is thickenedthe far edge of the wing is the iliac crest ( Christa Iliaca ) - has an archedcurved shape, serves to attach the broad abdominal muscles. Frontdi it ends with the anterior superior iliac spine ( spina iliaca anterior superior ), and behind - the posterior superior iliac spine ( spina iliaca posterior superior ). These two spines are important for determining the size of the pelvis.Ischium forms the lower and posterior thirds of the pelvic bone. Sheconsists of a body involved in the formation of the acetabulum and a branchischium. The body of the ischium with its branch forms an angle, openlocated anteriorly, in the area of ​​the angle the bone forms a thickening - the ischial tuberosity(tuber ischiadicum ). The branch is directed anteriorly and upward and connects with the lowerher branch of the pubic bone. There is a protrusion on the back surface of the branch - ischial spine (spina ischiadica). On the ischium there are two notches: greater sciatic notch ( incisura ischiadica major ), located below the posterior superior iliac spine, and the lesser sciatic notch ku (incisura ischiadica minor).

Pubic or pubic bone forms the anterior wall of the pelvis, consists of the bodyand two branches - the upper one ( ramus superior ossis pubis) and lower (ramus inferior ossis pubis ). The body of the pubis forms part of the acetabulum. TogetherThe connection between the ilium and the pubis is the iliopubis eminence (eminentia iliopubica).

The superior and inferior rami of the pubic bones connect to each other in frontthrough cartilage, forming a sedentary joint, a half-joint ( symphysis ossis pubis ). The slit-like cavity in this connection is filled with liquid andincreases during pregnancy. The lower branches of the pubic bones formthis angle is the pubic arch. Along the posterior edge of the superior ramus of the pubispubic ridge stretches ( crista pubica ), passing posteriorly into linea arcuata of the ilium.

Sacrum(os sacrum ) consists of 5-6 vertebrae motionlessly connected to each other, the size of which decreases downwards. The sacrum has the shape of a truncatedfine cone. The base of the sacrum faces upward, the apex of the sacrum (narrow)part) - downwards. The anterior surface of the sacrum has a concave shape; on itthe junctions of the fused sacral vertebrae are visible in the form of transverserough lines. The posterior surface of the sacrum is convex. Along the midlineThe spinous processes of the sacral vertebrae are fused together.First sacral vertebra connected to V lumbar, has a protrusion - sacral promontory (promontorium).

Coccyx (os coccygis ) consists of 4-5 fused vertebrae. It connectsusing the sacrococcygeal articulation with the sacrum. In braid connections There are cartilaginous layers in the pelvis.

The female pelvis from an obstetric point of view

There are two sections of the pelvis: the large pelvis and the small pelvis. The border between them is the plane of entry into the pelvis.

The large pelvis is limited laterally by the wings iliac bones, behind -last lumbar vertebra. In front it has no bony walls.

The small pelvis is of greatest importance in obstetrics. Through the small pelvis occursthe birth of the fetus is taking place. Does not exist simple ways pelvic measurements.At the same time the dimensions large pelvis easy to determine, and based on them you can judge the shape and size of the small pelvis.

The pelvis is the bony part of the birth canal. Shape andThe size of the small pelvis is very important during labor and determining the tactics of its management. With sharp degrees of narrowing of the pelvis and its deformation,In the future, childbirth through the natural birth canal becomes impossible, and women Well, they give birth by caesarean section.

The posterior wall of the small pelvis consists of the sacrum and coccyx, the lateral ones - the se-long bones, anterior - pubic bones with l coronal symphysis. Top-The lower part of the pelvis is a continuous ring of bone. In the middle andlower thirds of the wall mthe scarlet pelvis is not solid. In the lateral sections there are large and small sciatic foramina ( foramen ischiadicum majus etminus), limited respectively by the major and minor sciatic notches (incisure ischiadica major et minor) and withmatings ( lig. sacrotuberale, lig. sacrospinale ). The branches of the pubic and ischial bones, merging, surroundobturator foramen ( foramen obturatorium ), having the shape of a triangle with rounded corners.

In the small pelvis there are an entrance, a cavity and an exit. In the pelvic cavity there is a secretionThere are wide and narrow parts. In accordance withthis distinguishes in the small pelvis four classical planes ( rice. 1 ).

Plane of entry into the pelvis anteriorly limited by the upper edge of the symphysis andthe upper inner edge of the pubic bones, on the sides - by arcuate linesilium and posteriorly - the sacral promontory. This plane has the shapetransversely located oval (or kidney-shaped). It distinguishes three size (rice. 2): straight, transverse and 2 oblique (right and left). Straight size represents the distance from the superior inner edge of the symphysisto the sacral promontory. This size is called true or obstetric conjugates (conjugata vera) and is equal to 11 cm.

In the plane of the entrance to the small pelvis there are various they still expect anatomical conjugata anato - mica ) - distance betweenthe upper edge of the symphysis andsacral promontory.The size of the anatomical conjugate is equal to11.5 cm. Pepper size - the distance between the most distant sections of the aircurved lines. He co-is 13.0–13.5 cm. Large plane dimensions the entrance to the pelvis is represented byrepresent the distance betweendo sacroiliacarticulation of one sideus and the iliopubic eminence oppositethe wrong side. Rightoblique size is determinedfrom the right sacro-sub-iliac joint, le-vyy - from the left. These dimensions ry range from 12.0 to 12.5 cm .

The plane of the wide pelvic cavity the front is limited by the middle inner surface symphysis, on the sides - by the middle of the plates covering the acetabulum, on the back - by the junction of the II and III sacral vertebrae. In the wide part of the pelvic cavity there are

2 sizes: straight and transverse. Straight size— distance between the connection point I and III sacral vertebrae and the middle of the inner surface of the symphysis. It is equal to 12.5 cm. Transverse size is the distance between the middles of the internal surfaces of the plates covering the acetabulum. It is equal to 12.5 cm. Since the pelvis in the wide part of the cavity does not represent a continuous bone ring, oblique dimensions in this section are allowed only conditionally (13 cm each).

The plane of the narrow cavity of the pelvic cavity bounded in front by the lower edge of the symphysis, on the sides by the spines of the ischial bones, and behind by the sacrococcygeal joint.

In this plane there are also 2 sizes. Straight size - distance gap between bottom edgesymphysis and sacrococcygealyour joint. It is equal 11.5 cm. Transverse size - distance between axesthese ischial bones. He is 10.5 cm.

Plane of exit from the pelvis( rice. 3 ) is limited in front by the lower edge of the pubic symphysis, on the sides by the ischial tuberosities, and behind by the apex of the coccyx. Straight size - dis- standing between the bottom edgesymphysis and apex of the cop-chica. It is equal to 9.5 cm. Whenthe passage of the fetus through the birth canal (through the plane of exit from the pelvis)due to protrusion of the coccyxposteriorly this size increasesis 1.5-2.0 cm and becomeschanges to 11.0–11.5 cm. Transverse size - the distance between the internal surfaces of the seat leafy mounds. It is equal to 11.0 cm.

When comparing the dimensions of the small pelvis in different planes, it turns out that in the plane of the entrance to the small pelvis the transverse dimensions are maximum, in the wide part of the pelvic cavity the straight and transverse dimensions are equal, and in the narrow part of the cavity and in the plane of the exit from the pelvis, the direct dimensions are larger than the transverse ones.

In obstetrics, in some cases, the system is used parallel Goji planes( rice. 4 ). The first, or upper, plane (terminal) passes through the upper edge of the symphysis and the border (terminal) line. The second parallel plane is called the main plane and runs through the lower edge of the symphysis parallel to the first. The fetal head, having passed through this plane, does not subsequently encounter significant obstacles, since it has passed through a solid bone ring. The third parallel plane is the spinal plane. It runs parallel to the previous two through the spines of the ischial bones. The fourth plane, the exit plane, runs parallel to the previous three through the apex of the coccyx.

All classic planes of the pelvis converge anteriorly (symphysis) and fan out posteriorly. If you connect the midpoints of all straight dimensions of the small pelvis, you will get a line curved in the shape of a fishhook, which is called wire axis of the pelvis. It bends in the pelvic cavity according to the concavity of the inner surface of the sacrum. The movement of the fetus along the birth canal occurs in the direction of the pelvic axis.

As pregnancy progresses, lumbar lordosis increases due to a shift of the center of gravity from the region of the II sacral vertebra to the front, which leads to an increase in the angle of inclination of the pelvis. As the lumbar pelvis decreases, the pelvic inclination angle decreases. Up to 16-20 weeks. During pregnancy, no changes are observed in the posture of the body, and the angle of inclination of the pelvis does not change. By the gestational age of 32-34 weeks. lumbar lordosis reaches (according to I. I. Yakovlev) 6 cm, and
The angle of inclination of the pelvis increases by 3-4°, amounting to 48-50° ( rice. 5 ).The magnitude of the pelvic inclination angle can be determined using special devices designed by Sh. Ya. Mikeladze, A. E. Mandelstam, as well as manually. With the woman lying on her back on a hard couch, the doctor places her hand (palm) under the lumbosacral lordosis. If the hand moves freely, then the angle of inclination is large. If the hand does not pass, the angle of inclination of the pelvis is small. You can judge the angle of inclination of the pelvis by the relationship between the external genitalia and the thighs. With a large angle of inclination of the pelvis, the external genitalia and genital cleft are hidden between the closed thighs. With a low angle of inclination of the pelvis, the external genitalia are not covered by closed hips.

You can determine the angle of inclination of the pelvis by the position of both iliac spines relative to the pubic joint. The angle of inclination of the pelvis will be normal (45-50°), if at horizontal position of the woman's body, the plane drawn through the symphysis and the upper anterior iliac spines is parallel to the horizontal plane. If the symphysis is located below the plane drawn through the indicated spines, the angle of inclination of the pelvis is less than normal.

The small angle of inclination of the pelvis does not prevent the fixation of the fetal head in the plane of the entrance to the small pelvis and the advancement of the fetus. Childbirth proceeds quickly, without damage to the soft tissues of the vagina and perineum. A large angle of inclination of the pelvis often presents an obstacle to fixation of the head. Incorrect insertion of the head may occur. Soft injuries are often observed during childbirth. birth canal. By changing the position of the mother's body during childbirth, it is possible to change the angle of inclination of the pelvis, creating the most favorable conditions for the advancement of the fetus along the birth canal, which is especially important if the woman has a narrowing of the pelvis.

The angle of inclination of the pelvis can be reduced by lifting top part the torso of a lying woman, or in the position of the woman in labor on her back, bring the legs bent at the knee and hip joints to the stomach, or place a pad under the sacrum. If the pole is located under the lower back, the angle of inclination of the pelvis increases.

The pelvic bone is one of the largest and most powerful bones in the human body. It performs a lot of functions as it connects the torso with the lower limbs. It has a peculiar, atypical structure, since it performs the most important function of the pelvis - support. Also, thanks to the pelvic bone, a person is able to move, walk and sit. The bones of the pelvis make up the so-called pelvic girdle, which consists of an upper part (large pelvis) and a lower part (small pelvis).

The anatomical structure of the pelvic bone is determined by its important role. What is it? First of all, it should be noted that the sacrum, together with pelvic bone forms bony pelvis, which is the most massive joint, without which a person simply could not exist.

An individual feature of this anatomical region is the fact that up to approximately adolescence The pelvis consists of three bones that are separated from each other. And as they grow older, these bones grow together, forming one whole joint.

Thus, the pelvic bone has the following structure:

• ilium;
• pubic;
• ischium.

Ilium

It is a massive body with a large depression. It is this bone that helps attach the pelvic bone to the head of the femur.

Pubic

It consists of three elements and connects the ilium to the ischium.

Ischial

The connecting bone that attaches to the pubic bone and forms a closing opening with it.

As a result of such a powerful anatomical structure, a person moves with ease and does not experience any difficulties when walking. The unique structure of the pelvic bone causes a person to walk straight (in a vertical position), while ensuring balance while walking and distributing the load on all joints. After all, no one has ever seen a person lean to the right, left, forward or backward when walking. Upright walking is unique human body, none of the animals possess it. Also, the pelvic bone is a support for the spine, as it supports it in a straight position.

All these bones are connected to each other by one cartilage. The structure of the pelvic bone has gender differences. For example, the pelvic bone in women looks different than in men. It is wide and low, since its direct purpose is childbearing function. The so-called iliac wings and ischial processes in women are strongly turned to the sides, and the most massive and important muscles of the body are connected to the pelvic bones.

The pelvic bone performs the following functions:

1. Support. Thanks to the pelvic bones, a person stands firmly on his feet, since the entire weight of the body rests on it. The likelihood of fractures depends on its strength and strength.
2. Protective. This massive bone prevents damage internal organs, which are located in the lower abdomen, from direct mechanical impact.
3. Motor. The bones are so mobile that they allow you to move, run and sit calmly.

Pelvic bone injuries

Most often, pelvic injuries occur due to:

• car accidents;
• falling from a great height;
• increased bone fragility in older people (in the presence of osteopenia and osteoporosis).

Most frequent injuries occur due to car accidents and traffic incidents.

Falls from heights most often occur in everyday life (for example, when harvesting apples, plums or pears, people fall from trees); in construction, injuries often occur when builders fall out of the windows of a multi-story building or fall from scaffolding. When the pelvis is compressed due to collapses and falls of massive objects.

Pelvic fractures in older people are caused by thinning and brittle bones. In this case, even the most minor injuries lead to damage to the pelvic bones.

The most severe damage pelvic injuries are those in which internal organs are injured. Typically damaged:

• bladder;
• female organs;
• lower intestine.

Symptoms of a pelvic bone fracture

Symptoms of a pelvic fracture are divided into two main groups:

• local manifestations;
• general manifestations.

Local signs

These include the following symptoms:

• acute pain;
• deformation of the pelvic bones;
• hematoma;
• edema;
• bone crepitus (sound phenomenon);
• shortening of the limbs (when bone fragments are displaced).

Symptoms depend on which part of the pelvis is damaged.

General symptoms

These include:

• traumatic shock;
• massive bleeding;
• compression of nerve endings;
• tachycardia (rapid heart rate);
• drop in blood pressure (blood pressure);
• loss of consciousness.

As a result of severe blood loss, traumatic shock develops. Shock is accompanied by clammy sweat and pallor skin. Sometimes a fracture of the pelvic bone is accompanied by damage to internal organs. IN abdominal cavity a hematoma may form. If the urethra (urethra) is damaged, bleeding from the canal and urinary retention occur. A bladder rupture is manifested by the presence of blood in the urine (hematuria). Pelvic injuries have the following classification:

1. Fractures of certain bones. Such fractures heal quickly and are quite stable. Recovery period short, however, only on condition that the patient observes bed rest.
2. Unstable fractures, in which the pelvic bones are displaced horizontally.
3. Fracture of the acetabulum. Trauma occurs to the bottom or its edges.
4. Fractures accompanied by dislocations.
5. Bilateral and unilateral fractures.

Treatment of pelvic fractures

Immobilization is paramount in the treatment of pelvic fractures. It is especially relevant in the context of providing first aid medical care. To do this, the patient should be placed on his back, his legs should be moved slightly to the sides, and his knees bent. It is advisable for the patient’s comfort to place a bolster or pillow under the knees. This position of the patient is called the “frog pose.”

In some cases, when a certain part of the pelvis is fractured, this position is strictly prohibited. Since even the slightest spread of the legs causes the patient severe pain and may result in re-displacement of debris and additional injury. As a rule, in such situations the patient is placed on a stretcher and a pillow is placed under his feet. You can also bandage your legs together.

Currently, modern ambulances are equipped with vacuum immobilizing mattress stretchers and a compression pneumatic suit. Vacuum mattresses are filled with air, after which they take shape human body, which makes its transportation much more comfortable and less painful.

Compression pneumatic suits are used for extensive bleeding. Such a suit provides hemostasis and directs blood from peripheral vessels to central ones, which improves blood filling of the heart and blood. If such a suit is not available, a bandage can be placed on the pelvis to reduce bleeding.

In the hospital, the pelvic bones are immobilized, and they are also fixed in the correct physiological position. Then pain relief is carried out using anesthesia. An examination is then carried out and the patient is diagnosed.

Rehabilitation from such a complex injury can take long time, ranging from six months to a year. Therefore, it is best to avoid situations that could cause such extensive damage requiring complex treatment and long rehabilitation.

The pelvic girdle bears the weight of the entire upper body, and they rest against it lower limbs. This part of the body experiences a lot of pressure from both sides - from below and from above, it contributes to the movements of the lower extremities and protects important internal organs. The most important function of the pelvis is locomotor, facilitating movement of the body in space.

The differences between the human pelvis and the pelvis of other mammals are related to
with a vertical body position. Only humans have transverse dimensions
The pelvis is larger than the straight ones (antero-posterior). Even the pelvis of great apes
narrower and more elongated in length. In a human fetus, the pelvis has the same shape as
the same as the pelvis of four-legged mammals. Pelvic transformations begin
under the influence of mechanical loads: the weight of the torso, pressure in the hip
joint during movements, etc. Active formation of sexual differences
in the structure of the pelvis occurs during puberty under the influence
hormones. It is characteristic that with reduced ovarian function (female
gonads) slows down the formation of female
features - the pelvis remains relatively narrow.

Pelvic bones

The pelvic girdle, or pelvis, is a strong bony ring that is located in the lower part of the human torso skeleton. It is formed from almost motionlessly connected bones: the unpaired one - the sacrum and two massive, flat ones - the right and left pelvic bones. Wedged between the pelvic bones is the sacrum, to which is attached a small bone - the coccyx - a rudimentary remnant of the caudal skeleton.

In children under 16 years of age, each pelvic bone consists of 3 separate bones: the ilium, the ischium and the pubis, connected to each other by layers of cartilaginous tissue. After 16 years they grow together. At this place there is a deep hole - acetabulum. It includes the head femur, forming the hip joint.

The structure of the ischium
The ischium has a powerful ischial tuberosity, on which the human body rests when sitting. If a person stands, the ischial tuberosity is hidden by a thick layer of gluteal muscles and fatty tissue.

Structure of the pubic bone
The pubic bone has 2 branches connected to each other at an angle. These branches, together with the branch of the ischium, limit the large obturator foramen on the pelvic bone, covered with a dense membrane. The pubic bones on the right and left are connected to each other through cartilage - thus forming the pubic symphysis (half-joint), one of the joints of the pelvic girdle. The elevation of the skin above the symphysis is called the pubis.

The importance of the pubic symphysis is especially great for female body. By the time of childbirth, the cartilaginous layer between the pubic bones softens, and the gap inside it allows the bones to move apart and thereby slightly expand the birth canal.

Structure of the ilium
The ilium consists of a body and a thin wing, which expands upward and ends in a long crest. The ridge serves as the attachment point for the broad abdominal muscles. The depression on the inner surface of the wing forms the iliac fossa. It is in this fossa on the right that the cecum is located with vermiform appendix(appendix).

At the back of the ilium there is an articular surface shaped like auricle. It is tightly connected to exactly the same surface on the sacrum, forming a flat sacroiliac joint. This joint is strengthened on all sides by bundles of ligaments, which in terms of their strength are considered the most powerful in the human body.

Angle of inclination of the pelvic bones
The pelvic bones are the attachment point for the muscles of the abdomen, back and lower extremities. IN vertical position The human pelvis is tilted forward at an angle of 45-60 degrees relative to the horizontal plane. The size of the angle depends on posture; in women it is larger than in men.

Large and small pelvis

There are large and small pelvises. The boundary line separating them runs along the inner surface of the pelvic bones from the protrusion on the spine - the promontory (the junction of the last lumbar vertebra with the sacrum) to the upper edge of the pubic symphysis.

Big pelvis
The pelvis major is the upper section of the pelvis, formed by the unfolded wings of the ilium. It is the lower wall of the abdominal cavity and serves as a support for the internal organs.

Small pelvis
The small pelvis is located below the large pelvis and is limited from behind by the sacrum and coccyx, in front and from the sides by the ischial and pubic bones. It distinguishes between entrance, exit and cavity. The pelvic cavity contains the bladder, rectum and internal genital organs (ovaries, the fallopian tubes, uterus and vagina, prostate, seminal vesicles and vas deferens). The entrance to the small pelvis is open to the abdominal cavity and corresponds to the border line with the large pelvis. The exit from the pelvic cavity is closed by the muscles that form the pelvic diaphragm; in men they pass through urethra and rectum, in women - the urethra, rectum and vagina. From the outside, this area of ​​the body stands out as the perineum.

The pelvic organs differ from the abdominal organs in that they can
significantly change its volume: periodically filled
and the bladder and rectum are emptied, and the
and the uterus moves during pregnancy. It affects
on the functioning of other organs and blood supply.

Female and male pelvis

In no part of the skeleton are sex differences more pronounced than in the pelvis. Sex differences in the pelvis begin to appear in children aged 8-10 years. The average size of the male pelvis is approximately 2 cm smaller than the average size of the female pelvis. The female pelvis is wider and shorter than the male, the wings of the ilium are more deployed. The angle between the lower branches of the pubic bones is rounded in the form of a pubic arch, the promontory almost does not protrude into the pelvic cavity, and thanks to the wide, short and flat sacrum, the pelvic cavity has the shape of a cylinder.

The structure of the pelvis in men
In men, the pelvis is narrower and higher: the wings of the ilium are located almost vertically, the sacrum is strongly concave, and the promontory clearly protrudes into the pelvic cavity, the subpubic angle is acute. As a result, both the entrance and exit from the male pelvis are greatly narrowed, and its cavity itself has a conical shape.

The structure of the pelvis in women
During childbirth, the fetus moves through the pelvis in women, so its shape and size are of great importance for normal labor. The dimensions of the small pelvis are determined by indirect measurements of the large pelvis with obstetric calipers. Internal dimensions are determined by vaginal examination and ultrasound.

For example, the distance between the protruding tubercles on the iliac crest (the so-called superior anterior iliac spines) in women is normally 25-27 cm, and the distance between the most distant points of the crest on the right and left is 28-30 cm. The dimensions of the inlet and exit from the small pelvis, which in both direct and transverse dimensions are about 11-13 cm in women. The direct size of the exit from the small pelvis (the distance between the lower edge of the pubic symphysis and the apex of the coccyx), equal to 10 cm, during childbirth increases by 1.5-2 cm due to the posterior deviation of the tip of the coccyx.

In case of disturbances in the development of a girl, due to rickets, spondylitis, coxitis and other diseases and poor nutrition, neglect of classes physical culture or too big physical activity deviations are possible normal development pelvis - narrow pelvis. With a small degree of narrowing, childbirth is possible, but it can be long and difficult. With greater narrowing, obstacles arise for the passage of the fetus through the birth canal.

The structure of a woman’s bony pelvis is important in obstetrics, since in addition to its supporting function for internal organs, the pelvis serves as the birth canal through which the emerging fetus moves. The pelvis consists of four bones: two massive pelvic bones, the sacrum and the coccyx (Fig. 3). Each pelvic (nameless) bone is formed by fused bones: the ilium, pubis and ischium. The pelvic bones are connected through a pair of almost motionless sacroiliac joints, a sedentary semi-joint-symphysis and a mobile sacrococcygeal joint. The joints of the pelvis are strengthened by strong ligaments, and they contain cartilaginous layers. The ilium consists of a body and a wing, which is expanded upward and ends with a long edge - a crest. In front, the ridge has two projections - the anterosuperior and anterior-inferior spines. Similar projections are also present on the posterior edge of the crest - the posterosuperior and posteroinferior spines.

The ischium consists of a body and two branches. The superior branch runs from the body downwards and ends at the ischial tuberosity. The lower branch is directed anteriorly and upward. On its posterior surface there is a protrusion - the ischial spine.

Rice. 3. Female pelvis: 1 - sacrum; 2 - ilium (wing); 3 - anterosuperior spine; 4 - anterior inferior spine; 5 - acetabulum; 6 - obturator foramen; 7 - ischial tuberosity; 8 - lawn meadows; 9 - symphysis; 10 - entrance to the pelvis; 11 - unnamed line

The pubic bone has a body, superior and inferior branches. On the upper edge of the horizontal (superior) ramus of the pubic bone there is a sharp ridge, which ends in front with the pubic tubercle. The sacrum consists of five fused vertebrae and has the shape of a truncated cone. The base of the sacrum articulates with the V lumbar vertebra. On the anterior surface of the base of the sacrum a protrusion is formed - the sacral promontory (promontorium). The apex of the sacrum is movably connected to the coccyx, which consists of 4-5 undeveloped fused vertebrae.

There are two sections of the pelvis: large and small. Between them runs the border, or nameless, line. The large pelvis, unlike the small one, is accessible for external examination and measurement. The size of the small pelvis is judged by the size of the large pelvis.

The pelvis is the narrow part of the pelvis. During childbirth, it is the bony part of the birth canal. In the small pelvis there are an entrance, a cavity and an exit. The pelvic cavity has a narrow and a wide part. In accordance with this, four planes of the small pelvis are conventionally distinguished. The plane of entrance to the small pelvis is the boundary between the large and small pelvis. It has the shape of a transverse oval with a notch corresponding to the sacral promontory.

At the entrance to the pelvis the largest
the size is transverse. In the cavity of the small
The pelvis is conventionally divided into the plane of the wide part of the pelvic cavity, which has the shape of a circle, since its straight and transverse dimensions are equal, and the plane of the narrow part of the pelvic cavity, where the straight dimensions are slightly larger than the transverse ones. The plane of the exit of the small pelvis, like the plane of the narrow part of the pelvic cavity, has
the shape of a longitudinally located oval, where the direct dimension prevails over the transverse one.

It is practically important for the obstetrician to know the following dimensions of the small pelvis: true conjugate, diagonal conjugate and direct size of the pelvic outlet. The true, or obstetric, conjugate is the size of the entrance to the small pelvis, i.e., the distance from the sacral promontory to the most prominent point on the inner surface of the pubic symphysis. Normally it is 11 cm (Fig. 4).

The distance between the sacral promontory and the lower edge of the symphysis is called the diagonal conjugate, determined by vaginal examination and is equal to an average of 12.5-13 cm. The direct size of the pelvic outlet goes from the top of the coccyx to the lower edge of the symphysis: it is normally 9.5 cm. During childbirth, as the fetus passes through the pelvis, this size increases by 1.5 -2 cm due to the posterior deviation of the tip of the coccyx.

The born fetus passes through the birth canal in the direction of the wire axis of the pelvis, which is a line curved anteriorly (towards the symphysis) connecting the central

three of all direct pelvic sizes. Soft fabrics The pelvis covers the bony pelvis from the outer and inner surfaces. There are ligaments that strengthen the joints of the pelvis, as well as the muscles. The muscles located at the pelvic outlet are especially important. They cover the bony canal of the small pelvis from below and form the pelvic floor (Fig. 5). Part pelvic floor, located between the posterior commissure of the labia and the anus, is called the obstetric or anterior perineum. The part of the pelvic floor between the anus and the tailbone is called the posterior perineum. The pelvic floor muscles together with the fascia form three layers. This arrangement of muscles is of great practical importance during childbirth during expulsion of the fetus, since all three layers of muscles

The pelvic floor stretches and forms a wide tube, which is a continuation of the bony birth canal.

The most powerful is the upper (inner) layer of the pelvic floor muscles, which consists of the paired levator muscle. anus, and is called the pelvic diaphragm.

The middle layer of muscles is represented by the urogenital diaphragm, the lower (external) by several superficial muscles converging in the tendon center of the perineum: bulbospongiosus, ischiocavernosus, superficial transverse perineal muscle and external rectal sphincter.

The pelvic floor performs the most important functions, providing support for the internal genital organs and other abdominal organs. Failure of the pelvic floor muscles leads to prolapse and prolapse of the genital organs, bladder, and rectum.

The anatomy of the human pelvis is quite complex. This is facilitated by high load and wide range functions performed. The human pelvis connects the torso and lower limbs; accordingly, pressure is exerted both from above and from below.

It is interesting that out of all the diversity of mammals on the planet, it is humans that have pelvic sizes of cross section more than in the anterior-posterior. Moreover, in intrauterine development The shape of the fetal pelvis is the same as that of four-legged mammals, but changes over time.

Due to the nature of gender differences and the characteristics of the body, the pelvic bone of women is wider and lower. Its wings and tubercles of the ischial region are more spread out to the sides to facilitate pregnancy and childbirth. Differences in the structure of the pelvis begin to form immediately after the onset of the first menstruation (under the influence of female sex hormones).

Interestingly, with a lack of female sex hormones, against the background of reduced ovarian function, the anatomy of the female pelvis changes (becomes narrow) due to a slowdown in the formation female characteristics.

What functions does the human pelvis perform?

IN anatomical structure In the human body, the pelvis is of great importance, as it performs important functions for the body:

• supporting - the spinal column is attached to it;
• protective - human organs are located inside the pelvic cavity (bladder, large intestine, female and male genital organs);
• the pelvis functions as the center of mass of the human skeleton;
• hematopoietic - due to great content red bone marrow.

Protection

One of essential functions The pelvis is considered protective. The anatomy of the human body is such that almost all reproductive organs, the bladder and some abdominal organs are located in the pelvic area.

All these organs are protected from mechanical damage and displacement by bone tissues of the pelvic cavity.

This is especially important for women when carrying a child. The pelvic floor in the form of a junction of the sacrum and ilium is connected by ligaments and supports the uterus in the required position.

Pelvic bone structure

The pelvic bone is one of the most massive bone structures of the human body, and its structure and geometric shape are determined by its main function – support. It is formed by three sections: the ischial, pubic and iliac. Moreover, before the onset of puberty, the sections are separated by cartilage tissue, and at the age of 14-17 years the sections fuse and become one single pelvic bone.

The fusion of the sections occurs in areas with the greatest loads - in the area of ​​the acetabulum. The head of the femur is located in the acetabulum and thus forms the hip joint.

The iliac pelvis is located above the acetabulum and consists of a wing and a body. The wing at the end has a kind of ridge to which they are attached. muscle fibers abdominal cavity. From the back ileum The surface of the bone is connected to the joint of the sacrum (sacroiliac joint).

The pubic region is located below the acetabulum in front. It consists of two branches connected at an angle. At the junction of the branches there is cartilage tissue. All together is the pubic symphysis. During the restructuring of the female body for childbirth, the cartilage tissue softens and the bones move apart so as not to impede the baby’s exit from the birth canal.

The ischial region is located symmetrically to the pubis at the back. Like the pubis, it is located below the acetabulum. The bone tissues of the ischial region have powerful tubercles that are covered with muscle and fatty tissue. It is the tubercles that support a person when he is in a sitting position.

The human pelvis is formed by the pelvic structures, the sacrum and the coccyx. Together they form a ring-shaped pelvic cavity.

Hip joint

One of the most important joints The human joint that allows you to walk, run or move objects is the hip joint.

The formation of the joint begins in the womb. After birth, it partially consists of a cartilaginous hyaline layer, and at 4-5 months the cartilage ossifies. At the same time, intensive growth of the femur bones occurs. During the process of growing up, the hyaline cartilage completely ossifies and growth stops. In the following, the form mutual arrangement and the structure of human bones is constantly undergoing change.

The hip joints consist of two acetabulums of the pelvic bone and a pair of femoral heads. The shape of the joint corresponds to a spherical one, since the acetabulum has the appearance of a semi-spherical shape, which is filled with fatty tissue, and there is a cartilaginous rim along the edges. Structure hip joint due to the nature of the functions performed.

The ball-shaped head of the femur, covered with cartilage, is connected by the femoral neck to the bone itself (acetabulum). Outside surface The joint is covered by a durable capsule. There are several ligaments inside the joint. For example, the femoral head ligament absorbs stress on the femur bone during motor activity, and also protects the feeding vessels inside it.

The iliofemoral ligaments are the strongest in the entire human body, and their thickness is about 8-10 mm. Their function is to slow down the extension and internal rotation of the hip. The pubofemoral pair of ligaments, on the contrary, inhibits hip abduction in an extended position.