Women's pelvic organs. What is included in the pelvic organs in women - we study anatomy. The structure of the pelvic bones of a woman Clinical anatomy of the female pelvis

In the medical literature, the intricate definition of the concept of the small pelvis in women is accompanied by a photo or picture, where the names of organs and bones are signed in Latin. It is difficult for a person who is far from medicine to understand the meanings of these terms and to delve into medical terminology, but this knowledge, at times, turns out to be very useful. So what hides a woman's small pelvis?

The pelvis refers to the girdle of the lower extremities. Responsible for a reliable skeletal connection of the legs with the body due to the bone-ligamentous base of the pelvis and hip joints.

It consists of two pelvic bones, each of which is usually divided into three parts:

  • iliac;
  • ischial;
  • pubic.

Until about the age of 16, such a division is due to the fact that the pelvic bone is divided by cartilage into 3 parts with similar names. As they grow older, the cartilages ossify, thereby forming a single bone plate, and such a gradation remains and is more of a conditional character.

In the center of the ilium on the outer surface is the acetabulum - a deep hemispherical depression necessary for articulation with the femoral head.

Fact! Due to this, a strong connection of the upper body with the lower limbs is formed, which is also necessary for the performance of the motor function.

The bone ring is formed by the connection of two pelvic bones with the sacrum and coccyx. The border in this case will be the so-called borderline or, as it is also called, the nameless line. Its conditional location can be determined by the following bones:

  • iliac (arc-shaped lines);
  • sacrum (his cape);
  • pubic (their crests);
  • pubic symphysis (upper edge).

What is above is the upper section, also called the large pelvis, respectively, the narrow pelvis is located below, which has other names - narrow, true.

Bone borders of the pelvis

There is a bone restriction of the large pelvis only on three sides, it is absent in front. On the sides of its borders define the ilium, behind - the vertebrae of the lumbar spine.

The structure of the small pelvis includes more bones. It includes:

  1. In front - the pubic articulation (pubic symphysis), which is a semi-movable connection of the pubic bones.
  2. On the sides are the wings of the ilium.
  3. Behind - sacrum and coccyx.

Such atypical structure of the small pelvis allows it to perform the following functions:

  1. Maintain balance.
  2. Distribute the high load of the upper body.
  3. Serve as a support for the spine.

In addition, the pelvis is a protective structure for the internal organs, and the skeleton of the female pelvis differs from the male. This is due to the fact that women are genetically programmed to perform the reproductive function, that is, to carry and give birth to a child.

The structure of the female pelvis has its own anatomical features:

  1. His bones are much thinner and do not differ in such massiveness as those of the male.
  2. A wide and less concave sacrum, the cape protrudes less forward compared to the male.
  3. Wide and short symphysis.
  4. The wide entrance to the small pelvis has a transverse-oval shape, and a notch is located in the region of the promontory of the sacrum.
  5. The pubic angle reaches 90-100°.
  6. The coccyx protrudes less forward than in men.

The pelvis of women is larger and wider, but not as deep as that of men.

The cavity formed inside the joints of the bones serves as a kind of receptacle for several vital organs.

If you do not go into anatomical details, then in the small pelvis are the organs of the reproductive and digestive systems. They are very closely located among themselves and are surrounded on all sides by muscles and ligaments, which provide them with an anatomically correct position. The fibrous muscles of the perineum and the dense muscles of the pelvic diaphragm form the pelvic floor.

Interesting! The pelvic floor is in constant tone. It can, if necessary, contract or stretch - this happens, for example, during urination or in the process of coughing.

Vagina

This is an internal organ, which is an elastic muscular tube. Its upper part connects to the cervix, the lower part passes into the vestibule of the vagina, which is surrounded by the following organs:

  1. Clitoris.
  2. Large (external) labia.
  3. Small (inner) labia.

The entrance to the vagina is located in the middle between the urethra, located in front, and the rectum at the back. For virgins, the entrance is closed by the hymen. She may have one or more holes for menstrual flow.

ovaries

This is a female sex steam gland, which has an average weight of about 7 grams. They are attached to the uterus with ligaments and are mobile organs - their topography depends on the size and position of the uterus.

It is from here, from the ovaries, that the mature eggs begin their journey through the fallopian tubes, in which they are fertilized. After that, they continue to move towards the uterus, where the fetus will grow and develop until childbirth. If fertilization does not occur, the next cycle of menstruation begins.

The fallopian tubes

Otherwise they are called - fallopian tubes. This is a paired organ that connects the uterus and ovaries. The main task is to transport the eggs to the uterus and create a favorable environment for the fertilization of the egg.

Muscular hollow organ. Its front surface borders on the bladder, and the back - on the rectum. The slope of the uterus directly depends on the filling of these organs.

The walls of the uterus are multi-layered and extensible, which allows it to change its size along with the growth of the child during pregnancy. When the pregnancy comes to an end - the uterus, like a muscular organ, begins to contract, directing the child to its lower part - the neck. That, in turn, increases in size and opens to release the child into the birth canal and give rise to the birth process itself.

Bladder

Hollow organ of the urinary system. In addition to cumulative, it performs the function of excreting urine, it is located behind the pubis. The bladder is a muscular organ, so it can increase due to the fluid entering it from the kidneys up to 650 ml, after which the brain receives a signal to remove urine.

Rectum

This is the final part of the digestive system, located in the small pelvis. It is named so because of the absence of bends. At this site, the process of splitting the remaining food and the absorption of nutrients ends, and the accumulation of feces begins to further bring them out.

PID

PID is an inflammatory disease of the pelvic organs, the causes of which are many, but there are similar symptoms:

  1. Itching and swelling of the external genitalia.
  2. Discharge: purulent or simply copious.
  3. The appearance of pain in the lower abdomen is not clear origin.
  4. Painful urination.
  5. Pain that occurs during intercourse.
  6. irregular cycle.

The presence of even one or two of these symptoms is a reason to go to the gynecologist and identify the causes of the disease. To do this, you will need to pass tests and undergo certain studies, which are assigned individually, depending on each specific situation. The World Health Organization estimates that 40% of women who leave their infections untreated will develop PID. And every fourth will face infertility.

During therapy, conservative treatment is most often used. After the end of therapy, a second study is carried out to monitor the patient's condition. There are cases when surgical intervention is necessary, for example, when removing pus or uterine appendages. After such surgical procedures, physiotherapy and drug treatment are prescribed, aimed at restoring the normal environment of the vagina and strengthening the immune system. Prevention of PID is safe sex and proper selection of contraception.

The female pelvis is a volumetric cavity in which the genitals are located, and an important function is to ensure the flow of the birth process. The bones of the female pelvis have significant differences from the male. What are the sex differences in the pelvis?

The structure of the pelvis of a woman

The anatomy of a woman's pelvis undergoes modifications, starting from the birth of a girl and throughout the stages of growing up. In a born girl, its location is vertical, it is rather narrow, the entrance has an oval shape. In the process of growing up, it acquires a different shape and size of the pelvic bones.

Formation depends on a number of reasons:

  • genetic features;
  • external factors;
  • rickets;
  • infectious pathologies (for example, poliomyelitis);
  • physical activity;
  • injuries of the spine, legs.

The female pelvis is an articulation of several types of bones and ligaments between them. Muscle fibers of the spinal column and legs are attached to them.

Large pelvis

It is located in the upper part of the pelvic joint. Along its edges are the ilium, behind are the lumbar vertebrae, and in front of the anterior abdominal wall. The value may vary from the tension of the muscular apparatus of the abdominal press.

In terms of volume, a large pelvis can differ significantly from a small one. Judging by the size of the large, doctors conclude about the volume of the small, which is very important for determining the process of childbirth in women. Will it be natural childbirth or caesarean section. Quite often there are cases of the impossibility of independent childbirth due to the peculiarities of the anatomy of the pelvis in a woman.

Small pelvis

This is the bone structure of the birth canal. It consists of the upper plane, the bone cavity and the lower opening.

What is the small pelvis formed by:

  1. Posteriorly represented by the sacrum and coccyx.
  2. On the sides of the sit bones.
  3. In front of the symphysis and pubic bones.
  4. Between the two basins there is a border - an unnamed line.
  5. The female pelvis is represented by two systems.

reproductive system

This may include the following authorities:

  • the uterus and its neck;
  • two fallopian tubes;
  • two ovaries;
  • vagina;
  • labia.

In addition, large vessels and nerves are located in the pelvic area.

excretory system

Includes the following organs:

  • bladder;
  • rectum.

The musculature of the excretory system includes longitudinal and circular muscle fibers.

Types of bones

The pelvis of a woman, like men, performs a supporting function and distributes the weight of the body on the legs, which contributes to the motor activity of a person.

Bones of the female pelvis:

  • two pelvic (or nameless) bones;
  • coccygeal;
  • sacral.

Ligaments connect all kinds of bones.

Pelvic bone

In children under 15 years old, the innominate bone is a movable joint of three main bones:

  1. Ischial. It consists of two branches and a body. At the end of the upper branch is the ischial tubercle. The lower one is directed down and forward. It has an ischial spine.
  2. The pubic bone is represented by two branches: lower and upper. There is also a body. There is a comb on the top branch.
  3. Iliac. It consists of a wing and a body. At the top of the wing is a crest.

The pelvic bones grow together and become monolithic only after the child reaches 17-19 years of age.

coccygeal bone

The bone is represented by several rudimentary vertebrae. Usually there are 4 or 5 of them. It performs a supporting function and distributes the load on other structures of the pelvic joint. In the birth process, he can deviate a little back, to facilitate the process of giving birth to a child.

sacrum

These are 6 sacral vertebrae, monolithically interconnected. They are then joined into one bone. The sacrum looks like a massive triangle. In its upper part, the sacrum is connected to the 5th lumbar vertebra, and to the coccyx from below. In children, the components of the sacrum are interconnected by cartilage, while complete ossification and its transformation into a monolithic structure occurs at the age of 24-26.

Types of forms of the female pelvis

Anatomy is represented by four forms:

  1. Gynecoid. Not very deep cavity, oval entrance. The subpubic angle is 900. This is the ideal shape for the delivery of a woman. Usually women of average height and the same physique have this form.
  2. Android. More in line with the male form. It is characterized by a heart-shaped entrance, a funnel-shaped cavity. The pelvic outlet is compressed. The subpubic angle is less than 900. This form is often found in short women, their physique is quite dense.
  3. Anthropoid. The fifth lumbar vertebra is connected to the sacrum. The subpubic arch is large. This form is inherent in tall women. As a rule, natural childbirth proceeds without problems.
  4. Platipelloidal. The cavity is shallow. The angle is more than 900. The process of childbirth with this form proceeds normally.

The shape of the pelvis can be examined using x-rays.

male pelvis

It is usually smaller than the female by about 1.7 cm. The difference in size may depend on several reasons, for example, age, type of posture of a person.

Its cavity includes the following organs:

  • bowel loops;
  • appendix.

The pelvic inlet in men is narrower than in women, the coccyx is slightly less forward. Lymphatic, large blood vessels are also located here.

Differences between male and female

The anatomical features of the female pelvis differ from the male in a number of ways.

The difference between the female pelvis and the male pelvis begins to appear during the period of growing up of boys and girls.

The anatomy of the pelvic joint is quite complex. Violation of its integrity entails negative consequences. Such as dysfunction, lameness.

FEMALE pelvis from an obstetric point of view.

The bone pelvis consists of two pelvic bones, sacral and coccygeal bones, which are firmly connected through cartilaginous layers and connections.

The pelvic bone is formed from the fusion of three bones: longitudinal, ischial and pubic. They join in the region of the acetabulum.

The sacrum consists of 5-6 fixedly connected vertebrae, which merge into one bone.

The coccygeal bone consists of 4-5 underdeveloped vertebrae.

The bony pelvis in the upper section is open forward. This part is called the greater pelvis. Bottom part- this is a closed bone formation - the small pelvis. The border between the large and small pelvis is the terminal (nameless) line: in front - the upper edge of the symphysis and pubic bones, from the sides - arcuate lines of the ilium, behind - the sacral protrusion. The plane between the large and small pelvis is the entrance to the small pelvis. The large pelvis is much wider than the small one, it is bounded laterally by the wings of the ilium, behind by the last lumbar vertebrae, and in front by the lower part of the anterior abdominal wall.

All women undergo a measurement of the large pelvis. There is a relationship between the sizes of the large and small pelvis. By measuring the large pelvis, we can draw conclusions about the size of the small one.

Normal dimensions of the female pelvis:

  • distantia spinarum - the distance between the anterior upper bones of the longitudinal bone - 25-26 cm;
  • distantia cristarum - the distance between the distant points of the iliac crests - 28-29 cm;
  • conjugata externa - (external conjugate) - the distance from the middle of the upper edge of the symphysis to the upper corner of the Michaelis rhombus (measurements are made with the woman lying on her side) - 20-21 cm.

Rhombus Michaelis- this is an expansion of a depression in the sacral region, the limits of which are: from above - a fossa under the spinous process of the fifth lumbar vertebra (supracrine fossa), from below - points corresponding to the posterior superior iliac spines. The average length of a rhombus is 11 cm, and the diameter is 10 cm.

Diagonal conjugate- the distance from the lower edge of the symphysis to the most protruding point of the promontory of the sacral bone is determined during vaginal examination. With normal pelvic dimensions, it is 12.5-13 cm.

The size of the true conjugate (the direct size of the entrance to the small pelvis) is determined by subtracting 9 cm from the length of the outer conjugate or subtracting 1.5-2 cm from the length of the diagonal conjugate (depending on the Solovyov index).

Solovyov index - the circumference of the wrist-carpal joint, divided by 10. The index allows you to have an idea of ​​\u200b\u200bthe thickness of a woman's bones. The thinner the bones (index = 1.4-1.6), the greater the capacity of the small pelvis. In these cases, 1.5 cm is subtracted from the diagonal conjugate and the length of the true conjugate is obtained. With the Solovyov index

I, 7-1.8 - subtract 2 cm.

Pelvic tilt angle - the angle between the plane of the entrance to the small pelvis and the horizon is 55-60 °. Deviations in one direction or another can adversely affect the course of childbirth.

The height of the symphysis is normally 4 cm and is measured with the index finger during vaginal examination.
The pubic angle - with normal pelvic dimensions is 90-100 °.

Small pelvis is the bony part of the birth canal. The posterior wall of the small pelvis consists of the sacrum and the coccyx, the lateral ones are formed by the ischium, the anterior one is formed by the pubic bones and the symphysis. The small pelvis has the following sections: entrance, cavity and exit.

In the pelvic cavity, a wide and narrow part is distinguished. In this regard, four planes of the small pelvis are determined:

1 - the plane of the entrance to the small pelvis.
2 - the plane of the wide part of the pelvic cavity.
3 - the plane of the narrow part of the pelvic cavity.
4 - the plane of the exit from the pelvis.

The plane of the entrance to the small pelvis passes through the upper inner edge of the pubic arch, the innominate lines and the top of the promontory. In the plane of the entrance, the following dimensions are distinguished:

  1. Direct size - the distance from the sacral protrusion to the point that protrudes most on the upper inner surface of the symphysis - this is an obstetric, or true conjugate, equal to 11 cm.
  2. Transverse size - the distance between the distant points of the arcuate lines, which is 13-13.5 cm.
  3. Two oblique dimensions - from the iliosacral junction on one side to the iliopubic tubercle on the opposite side of the pelvis. They are 12-12.5 cm.

The plane of the wide part of the cavity of the small pelvis passes through the middle of the inner surface of the pubic arch, on the sides through the middle of the acetabular cavities and behind - through the connection between the II and III sacral vertebrae.

In the plane of the wide part of the small pelvis, there are:

  1. Direct size - from the middle of the inner surface of the pubic arch to the junction between II and III sacral vertebrae. It is equal to 12.5 cm.
  2. The transverse dimension passes between the midpoints of the acetabulum. It is equal to 12.5 cm.

The plane of the narrow part through the lower edge of the pubic junction, on the sides - through the gluteal spines, behind -
through the sacrococcygeal junction.

In the plane of the narrow part they distinguish:

1. Direct size - from the lower edge of the symphysis to the sacrococcygeal junction. It is equal to II, 5 cm.
2. The transverse dimension between the distant points of the inner surface of the ischial spines. It is equal to 10.5 cm.

The plane of exit from the small pelvis passes in front through the lower edge of the symphysis, from the sides - through the tops of the gluteal tubercles, from behind - through the crown of the coccyx.

In the plane of exit from the small pelvis, there are:

1. Direct size - from the top of the coccyx to the lower edge of the symphysis. It is equal to 9.5 cm, and when the fetus passes through the small pelvis, it increases by 1.5-2 cm due to the deviation of the tip of the coccyx of the presenting part of the fetus.

2. Transverse dimension - between the distant points of the inner surfaces of the ischial tuberosities; it is equal to 11 cm.

The line connecting the midpoints of the direct dimensions of all planes of the pelvis is called the leading axis of the pelvis, and has the form of a forward concave line. It is along this line that the leading point passes through the birth canal.

The main differences between the female pelvis and the male:

  • The bones of the female pelvis are thin and smooth compared;
  • The female pelvis is relatively wider, lower and larger in volume;
  • The wings of the ilium in women are more developed, so the transverse dimensions of the female pelvis are larger than the male ones;
  • The entrance to the small pelvis of a woman has a transverse oval shape, and in men it has the shape of a card heart;
  • The entrance to the small pelvis in women is larger and the pelvic cavity does not narrow down funnel-shaped, as in men;
  • The pubic angle in women is obtuse (90-100 °), and in men it is acute (70-75 °);
  • The pelvic tilt is greater in women (55-60°) than in men (45°).

Differences in the structure of the female and male pelvis begin to appear during puberty and become pronounced in adulthood. The bones of the female pelvis are thinner, smoother, and less massive than the bones of the male pelvis. The plane of the entrance to the small 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 cape).

Anatomically, the female pelvis is lower, wider and larger in volume. The pubic symphysis in the female pelvis is shorter than the male. The sacrum in women is wider, the sacral cavity is moderately concave. The pelvic cavity in women approaches the cylinder in outline, while in men it narrows downwards in a funnel-shaped manner. 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 converge in the male.

All of these features are very important in the process of childbirth.

The pelvis of an adult woman consists of 4 bones: two pelvic, one sacral and one coccygeal, firmly connected to each other.

Pelvic bone, or nameless, consists up to 16-18 years of 3 bones connected by cartilage in the region of the acetabulum: iliac, ischial and pubic. After the onset of puberty, the cartilages fuse together and form a solid bone mass - the pelvic bone.

On theilium distinguish between the upper section - the wing and the lower - the body. At the place of their connection, an inflection is formed, called an arcuate or nameless line. On the ilium, a number of protrusions that are important for the obstetrician should be noted. The upper thickened edge of the wing - the iliac crest - has an arcuate curved shape, serves to attach the broad abdominal muscles. It ends anteriorly at the anterior superior iliac spine and posteriorly at the posterior superior iliac spine. These two spines are important in determining the size of the pelvis.

Ischium forms the lower and posterior thirds of the pelvic bone. It consists of a body involved in the formation of the acetabulum, and a branch of the ischium. The body of the ischium with its branch forms an angle that is open anteriorly; in the region of the angle, the bone forms a thickening - the ischial tuberosity. The branch goes anteriorly and upwards and connects with the lower branch of the pubic bone. On the back surface of the branch there is a protrusion - the ischial spine. There are two notches on the ischium: the greater ischial notch, located below the posterior superior iliac spine, and the lesser ischial notch.

Pubic, or pubic, bone forms the anterior wall of the pelvis, consists of a body and two branches - upper and lower. The body of the pubis forms part of the acetabulum. At the junction of the ilium with the pubis is the iliopubic eminence.

The upper and lower branches of the pubic bones are connected to each other in front by means of cartilage, forming an inactive joint, a semi-joint. The slit-like cavity at this junction is filled with fluid and enlarges during pregnancy. The lower branches of the pubic bones form an angle - the pubic arch. Along the posterior edge of the upper branch of the pubic bone, the pubic crest extends, passing posteriorly into the linea arcuata of the ilium.

Sacrum consists of 5-6 vertebrae fixed to each other, the size of which decreases downwards. The sacrum has the shape of a truncated cone. The base of the sacrum is turned upwards, the top of the sacrum (narrow part) is downwards. The anterior surface of the sacrum has a concave shape; it shows the junction of the fused sacral vertebrae in the form of transverse rough lines. The posterior surface of the sacrum is convex. The spinous processes of the sacral vertebrae are fused along the midline. The first sacral vertebra, connected to the V lumbar, has a protrusion - the sacral promontory.

Coccyx consists of 4-5 fused vertebrae. It connects with the sacrococcygeal articulation to the sacrum. There are cartilaginous layers in the joints of the pelvic bones.

1. TOPIC OF THE LESSON: PELVIS FROM THE OBSTETRIC POINT OF VIEW: DIMENSIONS OF THE LARGE PELVIS, THE SMALL PELVIS, ITS PLANES AND DIMENSIONS. FETUS AS AN OBJECT OF BIRTH: HEAD OF THE FETUS, BONES OF THE SKULL, SUMS AND FELLOWS. DIMENSIONS OF THE HEAD OF THE TERM FETUS. POSITION OF THE FETUS IN THE UTERUS.

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

3. Meaning of the topic(relevance of the problem under study): Knowledge of anatomical formations, the size of a normal pelvis, the average size of the fetus is necessary for 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 pelvis of a woman and the head of the fetus; measure the pelvis and head of the fetus, as well as timely diagnose deviations 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 must know:

    the structure of the bone pelvis;

    pelvic planes, their boundaries and sizes, diagonal, anatomical and true conjugates;

    wire axis and angle of inclination of the pelvis;

    muscles and fascia of the 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 appearance);

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

The student must be able to:

    show on the model 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 determine with vera;

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

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

    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 for the lesson:

1. Tables

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

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

4. Obstetric simulator with a doll.

5. Model of the bone pelvis.

6. Model "Doll".

7. Tazomer, measuring tape.

8. Obstetric stethoscope.

8. Annotation of the topic(summary)

Of great importance in obstetrics is the bone pelvis, which forms a solid foundation for the 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 It is a strong container for the internal genital organs of a woman, the rectum, bladder and surrounding tissues. The woman's pelvis forms the birth canal through which the fetus is born. The development and structure of the pelvis is of 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 change. The development of the pelvis, as well as 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 of the trunk is transferred to the pelvis through the spinal column. When standing and walking, pressure from the lower extremities joins 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 dimensions. In addition, the sacrum, under the influence of pressure from above, rotates around its horizontal axis so that the cape descends and begins to protrude into the entrance to the pelvis. In this regard, the entrance to the pelvis gradually takes the form of a transverse oval with a notch in the promontory area. When the sacrum is rotated around the horizontal axis, its tip should have moved backward, but it is held by the tension of the sacrospinous and sacrotuberous ligaments. As a result of the interaction of these forces, a curve of the sacrum (sacral cavity) is formed, which is typical for the pelvis of an adult woman.

Differences between the female and male pelvis begin to be detected 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 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 transversely oval, with a notch in the cape area; the entrance to the male pelvis resembles a card heart due to the sharper protrusion of the promontory;

7. The pelvic cavity in women is more extensive, in its outline it approaches a cylinder, curved anteriorly; the cavity of the male pelvis is smaller, it narrows downwards like a funnel;

8. the exit 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 coccyx protrudes anteriorly less than in the male pelvis.

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

The development of the pelvis can be disrupted under adverse conditions of intrauterine development associated with diseases, malnutrition and other disorders in the mother's body. Severe debilitating diseases, unfavorable living conditions during childhood and puberty can lead to a delay in the development of the pelvis. In such cases, features characteristic of the childish and youthful pelvis may persist until the woman's puberty.

PELVIC BONES

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

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

Ilium(os ilium) consists of two parts: the body and the wing. The body makes up a short, thickened part of the ilium, it participates in the formation of the acetabulum. The iliac wing is a fairly 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 ( anterior superior spine- spina iliaca anterior superior), below is the second protrusion (front-lower spine - spina iliaca anterior inferior). Under the anteroinferior axis, at the junction with the pubic bone, there is a third elevation - iliopubic tubercle(tuberculum iliopubicum). Between the anteroinferior and anteroinferior iliac spine is the lesser iliac notch, between the anteroinferior spine and the iliopubic tubercle is the greater iliac notch. The iliac crest ends behind posterior superior iliac spine(spina iliaca posterior superior), below which is the second protrusion - the posterior iliac spine (spina iliasa posterior inferior). Under the posterior spine is a large sciatic notch (incisura ischiadica major). On the inner surface of the ilium, in the area of ​​​​the transition of the wing to the body, there is a ridge-like protrusion that forms an arcuate border, or nameless line (linea terminalis, s innominata). This line runs from the sacrum across the entire ilium, in front 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 ischial tuberosity(tuber ischiadicum). On the back surface of the lower branch there is a protrusion - ischial spine(spina ischiadica). The lower branch goes anteriorly and upwards and connects with the lower branch of the pubic bone.

Pubic bone, or pubic (os pubis), forms the front wall of the pelvis. The pubic bone consists of a body and two branches: the upper (horizontal) and the lower (descending). The short body of the pubic bone forms 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 crest, which ends in front with a pubic tubercle (tuberculm pubicum). The upper and lower branches of both pubic bones are connected to each other in front by means of a sedentary 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-like cavity filled with liquid; 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 the rather extensive obturator foramen (foramen obturatorium).

Sacrum(os sacrum) consists of five fused 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 - is turned up, the narrow part - the top of the sacrum - down. The posterior surface of the sacrum is convex, the anterior is concave, it forms the sacral cavity. On the anterior surface of the sacrum (in the cavity), four transverse rough lines are visible, corresponding to the ossified cartilaginous joints of the sacral vertebrae. The base of the sacrum (the surface of the 1st sacral vertebra) articulates with the 5th lumbar vertebra; a protrusion is formed in the middle of the anterior surface of the base of the sacrum - sacral promontory(promontory). Between the spinous process of the 5th lumbar vertebra and the beginning of the middle sacral crest, it is possible to feel the cavity ( suprasacral fossa), which is used when measuring the pelvis.

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

The bones of the pelvis 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, semi-joint.

There are two sections of the pelvis: the upper - 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, from the sides - nameless lines, behind - the sacral cape. The plane lying between the large and small pelvis is the plane of entry into the small pelvis, this plane is of great importance in obstetrics.

LARGE pelvis

The large pelvis is much wider than the small one, it is bounded laterally by the wings of the ilium, behind by the last lumbar vertebrae, and in front by the lower abdominal wall. The volume of the large pelvis can change in accordance with the contraction or relaxation of the abdominal muscles. The large pelvis is available for research, its dimensions are determined and quite accurately. By the size of the large pelvis, the size of the small pelvis is judged, which is not available for direct measurement. Determining the size of the small pelvis is important, since the fetus passes through the unyielding 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 length of the outer conjugate. The sacral rhombus (Michaelis rhombus) is also examined and measured.

SMALL pelvis

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

The 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 the coccyx, the lateral ones are formed by the ischial bones, the anterior - 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 of the pelvic wall is not continuous; they have obturator openings and ischial notches, limited by two pairs of ligaments (sacrospinous and sacrotuberous).

In the pelvis, there are the following departments: 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 cavity of the small pelvis, 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, from the sides - nameless lines, behind - the sacral promontory. The entrance plane has the shape of a kidney or a transverse oval with a notch corresponding to the sacral promontory. At the entrance to the pelvis, three sizes are distinguished: straight, transverse and two oblique.

Straight size- the distance from the sacral cape to the most prominent point on the inner surface of the pubic joint. 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 nameless lines. This size is 13-13.5 cm.

oblique dimensions two: right and left, which are equal to 12-12.5 cm. The right oblique size is the distance from the right sacroiliac joint to the left ilio-pubic tubercle, the left oblique size is from the left sacroiliac joint to the right ilio-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 reception. The hands of both hands are folded at a right angle, 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 hand 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 II and III sacral vertebrae to the middle of the inner surface of the symphysis; equal to 12.5 cm.

Transverse dimension- between the tops of the acetabulum; 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, laterally by the spines of the ischial bones, and behind by the sacrococcygeal articulation. There are two sizes: straight and transverse.

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

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

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

Direct pelvic outlet size 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 coccyx departs by 1.5-2 cm and the direct size increases to 11.5 cm.

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

The wire axis (line) of the pelvis. All planes (classical) of the small pelvis in front border on one or another point of the symphysis, and behind - on 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 in an anterior direction and fan-shaped diverge backwards. If you connect the middle of the direct dimensions of all the planes of the pelvis, you will get not a straight line, but a concave anterior (to the symphysis) line. This conditional line connecting the centers of all direct dimensions of the pelvis is called the wire axis of the pelvis. The wire axis of the pelvis is initially straight, it bends in the pelvic cavity in accordance with the concavity of the inner surface of the sacrum. In the direction of the wire axis of the pelvis, the 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 if the woman lying on her back is forced to pull the hips strongly to the stomach, which leads to the elevation of the womb. It can be increased by placing a roll-shaped hard pillow under the lower back, which will lead to the downward deviation of the womb. 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 muscular-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 muscles covered by fascia:

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

1. Bulbous-cavernous muscle(m.bulbo-cavernosus) wraps around the entrance to the vagina, attaches to the tendon center and the clitoris; when contracted, this muscle compresses the vaginal inlet.

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

3. Superficial transverse perineal muscle(m.transversus perinei superficialis) starts from the tendon center, goes to the right and left, is attached to the ischial tuberosities.

4. External sphincter of the anus(m.sphincter ani externus) - a muscle surrounding the end of the rectum. Deep bundles of muscles of the external sphincter of the anus begin at the top of the coccyx, wrap around the anus and end in the tendon center of the perineum.

II. Middle layer of pelvic muscles- the urogenital diaphragm (diaphragma urogenitale) occupies the anterior half of the exit of the pelvis. The urogenital diaphragm is a triangular muscular-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, running in the transverse direction to the ischial tuberosities. This part of the urogenital diaphragm is called the deep transverse perineal muscle. (m. transversus perinei profundus).

III. Upper (internal) the layer of muscles in the perineum is called the pelvic diaphragm (diaphragma pelvis). The pelvic diaphragm consists of a paired muscle that raises the anus (m.levator ani). Both broad muscles that lift the anus form a dome, the top of which is turned down and is attached to the lower rectum (slightly above the anus). The wide base of the dome is turned upwards and is attached to the inner surface of the walls of the pelvis. In the anterior part of the pelvic diaphragm, between the bundles of muscles that lift 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 consist of separate muscle bundles starting from various sections of the pelvic walls; this layer of pelvic muscles is the most powerful. All muscles of the pelvic floor are covered with fascia.

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

The muscles and fasciae of the pelvic floor perform the following important functions:

1. The pelvic floor is a support for the internal genital organs, helps to maintain their normal position. Of particular importance are the muscles that lift the anus. With the contraction of these muscles, the genital gap closes, the lumen of the rectum and vagina narrows. Damage to the muscles of the pelvic floor 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 stretch and form a wide tube, which is a continuation of the bone birth canal. After the birth of the fetus, the pelvic floor muscles contract again and return to their previous position.

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