Pelvic bones names. Pelvic girdle. Typical diseases, prognosis

The pelvic bone is the largest bony structure in the human body.

In addition to the function performed by the pelvis, determined by the property of its connection with the lower limbs, it is responsible for performing many functional tasks. Since one of the functions is to maintain normal support, the pelvic girdle is designed in such a way that in the female and male skeletal structure it is characterized by a difference in the functional features assigned to it.

Anatomy of the human pelvis

The anatomy of the human pelvis has clearly demarcated structures that interact with each other in various ways (from adjacent touch to direct dependence of one on the other). For each bone tissue, a certain function is predetermined, which must be successfully reproduced to avoid malfunction of the entire system of the skeleton, soft tissues, tendons and muscles.

The hip bone plays a significant role in the functioning of both legs, the part closest to the pelvis is articulated and surrounded by the hip joint. Since the anatomy of the skeletal column and adjacent bone structures of the female and male body are different, it is necessary to thoroughly understand the natural location and structure of the pelvis.

Pelvic bones

The pelvic bones of the human skeletal column are formed by the fusion of two components: the two innominate hip bones and the sacrum. Their strengthening occurs due to the ligamentous apparatus and joint, characterized by low mobility. The outlet and inlet openings of the pelvic bone tissue are covered with muscle tissue. This is a rather important structural feature that allows the natural process of childbirth to proceed normally.

Nerve fibers and vessels pass through multiple gaps in the pelvic bone.

The structure of the pelvic bones is such that its anterior and lateral zones end in the innominate bones. The posterior zone is limited by the sacrum and coccyx, which is the final structure of the spinal column.

Nameless Bones

The ilium is located in the area of the acetabulum and has a wing. Its inner surface is represented by a concave shape; intestinal loops are located in the adjacent space. A little lower, the innominate border overlaps the pelvic opening. In the female body, this place is important for medical diagnosis during pregnancy.

The outer surface is dotted with three lines to which the gluteal muscles are attached. The edge is presented in the form of a scallop, which ends in natural structures. The wings of the ilium, characterized by the presence of inner and outer layers, play an important role in the structure of the skeleton. Starting from the lower ones and ending with the iliac bones, bone structures are important anatomical landmarks in medical practice.

Differences between the female and male pelvis

A distinctive feature of the pelvic region is the difference in the structure of the skeleton of the female and male body. Since the female pelvis involves the reproduction of offspring, it is the main participant in childbirth. Medical practice emphasizes the special importance of not only clinical, but also x-ray anatomy.

Functions

The human pelvis is equipped with massive, strong joints and provides the main function – support. That is why the strength of the pelvic bone tissue is quite important, which allows it to withstand increased load. The part of the pelvic bone tissue that follows the pelvis consists of the thigh, kneecaps, legs and feet.

The pelvic girdle assumes the presence of the following functions of this part of the skeleton:

support and movement (the entire weight of the mass of the upper part of the human body is placed on the pelvis);
the protective function involves protecting the internal organs of the hip girdle.

Support and movement

The anatomical structure of a person implies the presence of a high-strength element in which the individual ones merge together, forming a strong, massive bone. In its central part on the outer surface there is a depression called the acetabulum, which articulates with the head of the femur. This place is the main point that takes on the pressure of body weight, as well as the epicenter of motor activity of the upper part of the human torso.

The conclusion follows: the pelvic bone must have an optimally strong structure, a large diameter, have sufficient depth and a steep edge. It is where the pelvic bones fuse during adolescence (ischium, ilium, pubis).

The human pelvis also performs the functions of movement in space. This function ensures a person's upright posture. Thanks to the pelvic bones, the skeletal axis and proper distribution of the body weight load on the lower limbs are supported.

Since the function of support and movement allows a person to carry out physical activity, with diseases of the musculoskeletal system, it loses its effectiveness.

Protection

Since the human body contains many vital organs, the protective function is of great importance for their normal functioning. Thanks to the protection, the safety of the spine, anterior abdominal wall, and other internal structures consisting of soft tissues, cartilage, tendons, and muscles is ensured.

Pelvic girdle consists of two pelvic bones. It provides strong and stable support to the lower limbs, which bear the body's weight. The pelvic bones connect to each other in front at the pubic symphysis (a disc of fibrocartilage). With the sacrum and coccyx, the two pelvic bones form a “medicine tray”-like structure called the pelvis. After a person is born, each pelvic bone consists of three separate bones: the ilium, the ischium, and the pubis. These individual bones eventually join to form one pelvic bone, the area of the joint being a deep hemispherical socket called the acetabulum (this socket connects to the head of the femur). Although the pelvic bone is a single bone, it is usually described as having three parts.

Ilium

Ilium is a large, flared bone that forms the largest and upper part of the pelvic bone. When a person places his hands on his hips, the iliac spines are felt. Each spine ends anteriorly as the anterior superior iliac spine (ASIS); and posteriorly as the posterior iliac spine (PSIS) (this spine is difficult to palpate, but its position is indicated by a depression of skin in the sacral region, approximately at the level of the second sacral foramen).

Ischium

Ischium is the lower, posterior part of the pelvic bone, shaped like an arch. At the base of the ischium there are rough and thickened ischial tuberosities (sometimes called “sitting bones” because when a person sits, their entire weight rests on the ischial tuberosities).

pubic bone

pubic bone is the front and lower part of the pelvic bone.

The pelvic cavity is an anatomical space limited by the bones of the pelvis. Depending on gender, the structure of this part of the body differs. In a woman, the area is more protected, since it contains important organs for conceiving and bearing a child. You can see the differences in more detail on the diagrams of the structure of the female and male pelvic organs. Injury to the pelvic cavity is fraught with anal incontinence, reproductive dysfunction, and pathologies of the genitourinary system.

Anatomy of the pelvis in men and women

In medicine, the small pelvis (in Latin pelvis minor) is the collection of bones and soft tissues located below the border line. In men, the pelvis is narrower and longer, in women it is shorter and wider. This is explained by the reproductive function inherent in the female body by nature. The male skeleton, in turn, must be durable, strong and withstand a variety of loads. The outlet from the small pelvis is closed by the pelvic and genitourinary diaphragms, formed from muscles and fascia.

The urogenital diaphragm in men is pierced by the urogenital canal, in women by the urethra and vagina. Both have their rectum passing through it.

Features of this area, characteristic of both sexes:

variability of volume, shape and position of organs;
several operational approaches to organs.

There are separate specializations for examinations and surgical interventions on the pelvic organs - gynecology and urology.

Skeletal system

The upper boundaries of the pelvic girdle are the iliac crests. You can feel them yourself if you place your hands on either side just below your waist. Long bone formations stretch from the sacrum and wrap around the lateral surfaces of the body.

The pelvis itself is a symmetrical bone formation (pictured on the right). Consists of the sacrum with the coccyx, a pair of innominate bones and a pair of pelvic bones. In turn, each nameless includes three interconnected bones:

ileum;
pubic;
sciatic

The place of their articulation is the acetabulum - a deep hole covered with cartilage. The iliac crest forms along the edge of the flat and curved ilium. Behind, in front and below it is surrounded by the iliac spines. On the posterior lateral inner surface of the ilium is the sacroiliac joint. Inferiorly, the bone passes into the ischium, and then into the ischial tuberosity. On the right and left, this zone is covered with muscle and adipose tissue, which creates support for a person when sitting.

Anteriorly and inferiorly, the ilium fuses with the pubis or pubis. The right and left sides of the womb are fused together using cartilage. To palpate this area, just find the triangle under the abdomen.

In women, the greater trochanters of the femur protrude more than in men. The amount of adipose tissue in this area predominates. Visually, it seems that the lower part is much wider than the shoulders.

Ligaments and muscles

Joints and ligaments provide connection between the left and right parts of the pelvic cavity. Several elements are involved in the formation of the pubic fusion:

symphysial surfaces of the pubic bones;
interpubic disc;
superior pubic ligament;
inferior arcuate pubic ligament.

Ligaments also strengthen the sacroiliac joint capsule. The dorsal ligaments run along the dorsal surfaces of the bones, and the ventral ligaments run along the ventral surfaces. The sacrospinous and sacrotuberous ligaments pass from the sacrum to the ischial tuberosity. With their help, the large and small sciatic notches turn into the sciatic foramina.

The iliopsoas ligament is responsible for connecting the bones to the vertebral region. It performs flexion and supination of the thigh in the hip joint, bends the lumbar spine with a fixed leg.

The pelvic muscles are called levators (pictured on the right). They are very elastic, capable of contracting and stretching greatly. The main task is to maintain the abdominal cavity. Other functions of the pelvic muscle group:

keep organs in an anatomically correct position;
contribute to the normal functioning of organs;
prevent urinary and fecal incontinence.

Being toned, muscles help women enjoy intimacy and facilitate the process of natural childbirth.

A special system of Kegel exercises has been developed to strengthen the pelvic muscles. They are aimed at maintaining tone, improving blood circulation and stimulating cell renewal. To achieve a long-term effect, classes must be regular.

The pelvic musculature consists of two layers:

perineum - the superficial layer of fibrous muscles;
pelvic diaphragm - a deep layer of dense, large muscles.

The fibrous muscles are directed from the inside to the outside and intertwine three openings: the sphincter, the urethra and the vagina. The latter is typical only for women. The vagina is an elastic muscular tube 7-12 cm long. Its walls consist of inner, middle and outer layers. The middle one is a smooth muscle frame, the bundles of which are directed in the longitudinal direction. In the upper part it passes into the muscles of the uterus.

The lower part of the vagina is much stronger than the upper part, however, over time it can also lose its elasticity. To control the process of contraction of the vaginal muscles, it is enough to change the intra-abdominal pressure.

To develop control of intra-abdominal pressure, there are pneumatic simulators. The most popular are vaginal balls.

Blood supply, lymphatic system and innervation

Blood flow to the pelvis and lower extremities is provided by ducts arising from the abdominal aorta. The most important role in this system is played by the internal iliac artery. Additional vessels involved in blood circulation:

superior rectal artery;
ovarian arteries;
median sacral artery.

The internal iliac artery is the medial branch of the common iliac artery. Its length is about 4 cm, in some it reaches 6 cm. In the area of the sciatic foramen, the vessel is divided into anterior and posterior trunks. Visceral and parietal branches depart from them, forming the vascular system of the pelvis.

The visceral branches are directed to the pelvic organs, and the parietal branches are directed to the walls of the pelvis.

The visceral branches of the internal iliac artery include:

superior cystic arteries;
uterine artery;
middle rectal artery;
internal pudendal artery.

The parietal branches are represented by the following vessels:

iliopsoas artery;
lateral sacral artery;
gluteal arteries;
obturator artery.

The outflow of blood to the heart occurs through veins or their plexuses. In particular, along the internal and external iliac veins.

The lymphatic system of the pelvis is represented by several groups of nodes:

Iliacs. They are located along the common and external iliac arteries. Lymph is received from the lower extremities, buttocks, perineum and lower abdominal wall.
Internal iliacs. Take lymph from large pelvic organs and pelvic walls. They pass along the artery of the same name.
Sacral. Lymph is collected from the rectum and the posterior wall of the pelvis. Located on the anterior surface of the sacrum.

The draining lymphatic vessels of the listed groups perfectly anastomose with the inferior vena cava and portal veins.

Lymphovenous anastomoses of the pelvis pose a danger if a woman has genital cancer. This increases the risk of tumor cells entering the bloodstream.

Pleasant or painful sensations are transmitted to the brain using nerve endings. If the system is working correctly, you should analyze the situation and identify the cause of the discomfort.

Two types of nervous system are involved in the innervation of the pelvic organs:

Somatic (animal). Transmits impulses from the skin, muscles, periosteum, pelvic bones and parietal peritoneum.
Autonomous (vegetative). Represented by the superior hypogastric plexus, sacral nerves and the pelvic section of the sympathetic trunk. Nerve fibers are located in the genitals, bladder, ureters, cecum and rectum, and appendix.

The nerve endings of the autonomic nervous system differ from the somatic nervous system in their incomplete myelin coverage. This significantly slows down the process of pain impulse passing through them. For a person, pain is felt as poorly localized and diffuse. Discomfort cannot be determined by palpation.

The innervation of the sigmoid and rectum, triangle of the bladder, urethra, upper vagina, cervix and sacrouterine ligaments is provided by sensory fibers of the parasympathetic system. The pain in these areas is sharp, radiating to the buttocks, lower back or lower limbs.

Sympathetic fibers serve as a link between the central nervous system (CNS) and the fundus of the uterus, the inner surface of the fallopian tubes, the broad ligaments of the uterus, the bottom of the bladder, the appendix, and the dome of the cecum. Symptoms of any pathological processes in these areas are localized in the lower abdomen.

Impulses from the ovaries, the lateral two-thirds of the fallopian tubes, the ureters and the surrounding cellular spaces move along afferent fibers to the spinal cord. They are responsible for pain in the umbilical area.

Excretory organs

An integral part of the pelvis are the excretory organs. Here are the bladder and ureters, urethra, rectum and anus. Depending on the gender, the arrangement of the elements changes. The main differences between the male and female excretory systems:

In a woman, the bladder is located in the lower part of the pelvis: in front of the vagina and ureters, behind the pubic bone. The length of the urethra is 3-4 cm.
In men, the bladder occupies the space between the pubic bone and the rectum. The urethra is much longer and extends through the penis.

Pelvic organs in women

The bladder acts as a reservoir for urine. Two ureters are attached to it on the posterior side. When enough fluid accumulates, nerve impulses travel to the brain and the person receives the urge to urinate. The walls of the bubble are very elastic, so they stretch easily. The process of excretion of urine occurs through the urethra (urethra). Since the female half has a wider and shorter organ, they urinate more often and faster.

The final link in the food chain is the rectum. The organ has curves where the sacrum and coccyx pass. In women, it also passes through the perineum and is adjacent to the vaginal wall.

In the rectum, the process of complete breakdown of food and accumulation of feces occurs. The lumen is closed by sphincters, which, upon receiving a signal from the brain, facilitate the passage of feces.

The area around the anus, where the mucous membrane meets the skin, is called hemorrhoidal. Hemorrhoids can form in it.

Reproductive system

The reproductive system is responsible for one of the most important human functions - reproductive. Any pathologies in this area can lead to infertility or difficulty conceiving. The only way to avoid this will be regular examination by a gynecologist or urologist, taking tests and knowing your body.

Every person must have information about how his reproductive system works. In a woman, it consists of the following organs:

labia minora and labia majora;
clitoris;
hymen (hymen or crown);
ovaries;
fallopian tubes;
uterus;
vagina.

For reproduction, eggs are of greatest value. Their maturation occurs in the ovaries. Then they come out and move through the fallopian tubes to the uterus. If conception does not occur during this period, menstruation occurs.

The male reproductive system also consists of external and internal genital organs. These include:

penis;
scrotum;
testicles;
epididymis;
prostate;
vas deferens;
urethra.

The formation and maturation of sperm occurs in the testicles. During sexual intercourse, they are mixed with seminal fluid and expelled during ejaculation.

The testicles synthesize male sex hormones - testosterone and androgen. They have the greatest impact during puberty.

Crotch

It is a mistake to consider the perineum as part of an exclusively female body. In fact, the term describes a complex of soft formations located between the pubic bones in front, the ischial tuberosities on the sides and the coccyx in the back. The space is occupied by muscles and fascia (sheaths of connective tissue).

Conventionally, the perineum can be divided into two parts: the anterior (genitourinary diaphragm) and the posterior (pelvic diaphragm). The border between them is the line connecting the ischial tuberosities. In women, the vagina and urethra pass through the anterior diaphragm, while in men only the urethra passes through. The anus is located in the area of the posterior diaphragm.

The perineum, like any other area, is susceptible to various diseases. A boil or herpes, diaper rash, infectious lesions, and hernias may appear here. In girls at an early age and adult men, specific tumors - teratomas - occur. The formations have a high chance of becoming malignant. The main symptoms of any pathology are severe pain, swelling, and bleeding.

During the evolutionary development of man, changes occurred in his skeleton, including the improvement of the structure of the pelvis. Walking upright led to a significant increase in the load on the pelvic bones. As a result, they acquired the appearance of a bowl with a wide base, which allowed the lower limbs to effectively perform functional activities.

The structure of the human pelvis is a rather complex anatomical structure that changes depending on age.

In children, the pelvic bones are connected to each other using elastic ligaments. In adulthood, the pliable connective tissue joint is replaced by bone tissue.

The relative position of the components of the hip joint also changes. Such transformations occur in order to withstand the load of a growing organism.

Gender features of the structure

The anatomy of the pelvic girdle depends on the gender of the person. This is due to the fact that women of fertile age are able to bear and give birth to children. It was labor activity that influenced the structure of the pelvis. Gender characteristics include:

The transverse size of the pelvis in women significantly exceeds the longitudinal one. This wide shape provides support for the expanding uterus during pregnancy.
For the physiological location of the amniotic sac, the bony base of the pelvis has a flattened bottom.

The parameters of the pelvic girdle are important for the normal course of labor, so they are measured in all pregnant women. The size and shape are assessed by a gynecologist using a special device - a pelvis meter. An additional measurement is performed intravaginally. Ultrasound allows you to accurately determine the internal dimensions of the pelvis.

European researchers have proposed using differences in the pelvic girdle in the fetus as a factor confirming the gender of the unborn child. Therefore, when conducting an ultrasound examination, the specialist pays attention not only to areas of ossification, but also measures key parameters of the pelvic bones.

Pelvic functions

The specific structure of the pelvic bones is determined by their functions. In the process of evolutionary development, man began to move vertically, which increased the load on the lower parts of the skeleton. In this regard, the bone base was strengthened, and the ligaments were replaced with strong joints. Among the main functions of the pelvis are:

Support. The pelvic girdle bears the entire load of the upper half of the body.
Motor. The lower limbs are attached to the pelvic bones, allowing movement in space.
Maintaining balance. Due to changes in body position during development, a shift in the center of gravity occurred. The massive bones of the lower part of the body help stabilize it during various activities.
Protective. The pelvic bones serve as protection for the internal organs of the genitourinary and reproductive systems, and the lower parts of the digestive tract.
Participation in labor. The anatomical features of a woman’s pelvis allow her to create physiological conditions for the growing fetus. Due to hormonal levels, changes in the ligamentous apparatus occur. This causes displacement of the bones during childbirth and further restoration of the pelvic girdle in the postpartum period.

Structure

The anatomy of the human pelvis has long been no secret. The structure of the skeleton of the lower limb has been fully studied. The development of instrumental diagnostic methods, such as X-ray examination, magnetic resonance and computed tomography, ultrasound, has made it possible to track the origin, formation and age-related characteristics of the pelvic girdle.

In some Internet sources, the skeleton of the lower extremities is mistakenly combined under the general name of the hip bone. We will look at how things really are with the structure of the pelvis below.

Bony skeleton

The structure of the pelvis of a child and an adult is different. In childhood, the belt is represented by three bones connected by elastic ligaments. Between 14 and 16 years of age, the pliable connective tissue becomes calcified. There is a fusion of individual parts of the skeleton into one bone - the nameless bone. Let's take a closer look at each of them:

Ilium. It is the posterior part of the pelvic girdle, connecting to the spine. It consists of a body and a wing ending in a crest. This structure serves as the attachment point for the muscular corset of the abdominal wall. There is a fossa on the inner surface of the ilium. It is known for the fact that it contains the appendix on the right side of the body - part of the cecum, often involved in the inflammatory process.
Ischium. It is located between the ilium and pubis and is represented by the body and the branch. There is a massive mound on its surface, which bears the main load when a person sits. In a vertical position, this anatomical formation is not visualized, since a thick layer of subcutaneous fat and muscle fibers are located above it.
Pubic bone. The right and left pubic bones are connected to each other using cartilaginous tissue, forming the symphysis. Its role is great among women. During pregnancy, the properties of cartilage change. It becomes soft, which increases the distance between the pubic bones and expands the diameter of the birth canal. Above the symphysis there is a layer of fatty tissue that forms the pubis.

Hip joint

The pelvic girdle includes, with the help of which the lower limbs are attached. The junction of the ilium, ischium and pubis forms the acetabulum. It includes the articular part of the femur - the head. Thanks to the special shape of the surface, the hip joint is capable of movements in three planes, and the developed ligamentous apparatus prevents their excessive amplitude.

The articular part of the articulation is covered with hyaline cartilage. It ensures smooth sliding of the femoral head in the acetabulum. This is also facilitated by the synovial fluid filling the joint cavity. In addition to the lubricating function, it provides:

cartilage nutrition;
reduces the load, having a shock-absorbing effect.

The normal functioning of the hip joint guarantees a stable body position and ensures a full range of movements.

Vessels

The blood supply to the pelvic girdle is developed. It is provided by the large iliac artery, which divides into smaller branches. The capillary network interweaves the internal organs and nourishes the musculoskeletal system. The outflow of blood occurs into venous vessels located superficially or in depth.

Pathology

Pathology of the pelvic girdle is most often associated with traumatic exposure. The most dangerous are those in which there is damage to internal organs. Violation of the integrity of the intestines and bladder significantly complicates the patient’s condition, worsening the prognosis for recovery.

Among diseases of the hip joint, a special place is occupied by dysplastic pathology associated with a congenital defect of the connective tissue of the joint. Modern diagnostic and treatment methods make it possible to effectively help patients, however, in advanced cases, the only way to help a person is.

The pelvic girdle bears the weight of the entire upper body, and the lower limbs also rest against it. 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 tail 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 fossa - the acetabulum. The head of the femur enters it, 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 significance of the pubic symphysis is especially great for the 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 with the vermiform appendix (appendix) is located.

At the back of the ilium there is an articular surface shaped like the 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 a vertical position of a person, the 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, 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, through which the urethra and rectum pass in men, and the urethra, rectum and vagina in women. 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.

If there are disturbances in the development of a girl, due to rickets, spondylitis, coxitis and other diseases and poor nutrition, neglect of physical education or too much physical activity, deviations in the normal development of the pelvis are possible - a 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.