Why does the connection of the pelvic bones with the sacrum have low mobility? Connection of the pelvic bones with the sacrum. Development of the pelvic bones

Hip bone (os coxae) in adults it looks like a whole bone. Until the age of 16, it consists of three separate bones: the ilium, the ischium and the pubis. The bodies of these bones on the outer surface form the acetabulum, which serves as the junction of the pelvic bone with the femur.

Ilium (os ilium) the largest, occupies the upper posterior sections of the pelvic bone. It consists of two sections - the body and the wing of the ilium. Upper curved edge of wing called iliac crest. In front of the iliac crest there are two protrusions - the superior and inferior anterior iliac spines, and below - the greater sciatic notch. The inner concave surface of the wing forms the iliac fossa, and the outer convex surface forms the gluteal surface. On the inner surface of the wing there is an auricular surface - the place of articulation of the pelvic bone with the sacrum.

Ischium (os ischii) consists of a body and a branch. Here are the ischial tuberosity and ischial spine, etc. greater and lesser sciatic notches. The branch of the ischium, fused in front with the lower branch of the pubic bone, thus closes the obturator foramen of the pelvic bone.

pubic bone (os pubis) has a body, upper and lower branches. At the junction of the bodies of the pubic and ilium bones there is an iliopubic eminence. And along the transition of the upper branch to the lower, in the area of ​​the medial surface, there is a symphysial surface - the junction of the pelvic bones in front.

acetabulum formed by the fused bodies of the ilium, ischium and pubic bones. Its articular semilunar surface occupies the peripheral part of the cavity.

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1. Sacroiliac joint- a tight joint formed by the ear-shaped articular surfaces of the sacrum and ilium. Blood supply from aa. lumbalis, iliolumbalis et sacrales laterales. Innervation: branches of the lumbar and sacral plexuses.

2. Pubic symphysis connects both pubic bones to each other. Between the surfaces of these bones facing each other there is a fibrocartilaginous plate in which the synovial cleft is located.

3.Sacrotuberous and sacrospinous ligaments-strong interosseous ligaments connecting the sacrum with the pelvic bone on each side: the first - with the ischial tuberosity, the second - with the adjacent spine. The described ligaments transform the greater and lesser sciatic notches into the greater and lesser sciatic foramina.

4. Obturator membrane- a fibrous plate that covers the obturator foramen of the pelvis. Attaching to the edges of the obturator groove of the pubic bone, it turns this groove into the obturator canal.

Pelvis as a whole

Both pelvic bones form the pelvis, which serves to connect the torso with the free lower limbs. The bony ring of the pelvis is divided into two sections: the upper one - the large pelvis, and the lower, narrower one - the small pelvis. Below, the pelvic cavity ends with the inferior pelvic aperture, the ischial tuberosities, and the coccyx.

The bones of the female pelvis are generally thinner and smoother than those of men. The wings of the ilium in women are more turned to the sides. The entrance to the female pelvis has a transverse oval shape and is wider; the female sacrum is relatively wider and at the same time flatter. The tailbone protrudes forward less. The pelvic cavity in its outline approaches a cylinder. The female pelvis is low, but wider and more capacious.

What parts (divisions) does the limb of land-dwelling four-legged animals consist of?

What types of bone connections exist?

They consist of three sections: shoulder, forearm and hand (front) or thigh, lower leg and foot (back).

Joints, ligaments and cartilage.

1. The father put the child on his shoulders. What bones of the father does the baby rely on? What bones do anatomists call shoulders?

The bones of the arms are attached to the bones of the body by means of the shoulder blades and collarbones. They make up the skeleton of the shoulder girdles - the child leans on them. The shoulder is formed by one long humerus bone.

2. List the bones of the arm and leg and indicate how they differ.

The skeleton of the hand consists of three sections: the shoulder, forearm, and hand. The shoulder is formed by one long humerus bone. Two bones - the ulna and the radius - make up the forearm. They are located nearby. The hand is connected to the forearm. The small bones of the wrists of the metacarpus form a wide palm, and the phalanges form five flexible, movable fingers. The human thumb is opposed to the other four. This allows you to more securely hold various objects, such as a pencil, pen, hammer. The leg skeleton also consists of three sections: the thigh, lower leg and foot. The leg bones are very strong and durable. They can withstand the weight of the human body. The thigh is formed by the femur. This is the largest bone in our body. There are two bones in the lower leg - the tibia and fibula. The femur articulates with the bones of the lower leg using the knee joint. In the thickness of the tendon of the quadriceps muscle, which straightens the leg bent at the knee, there is a kneecap. The ankle joint also has great strength. The foot consists of three parts: the tarsus, metatarsus and phalanges. The largest bone of the tarsus is the calcaneus.

3. Rotate the hand so that the ulna and radius bones are parallel to each other.

If the palm is facing up, the bones are parallel.

4. How to prove that the shoulder girdle increases range of motion?

You need to place your left hand on your right collarbone and begin to slowly raise your right hand. The clavicle of the right hand is motionless until the movement occurs due to the shoulder joint and until it reaches a horizontal position. Try to move your hand further, raising it above your head - the collarbone, and with it the scapula, will begin to move, since now the movement of the hand is due to the sternoclavicular joint. This joint also works when the arm moves forward and backward. To follow the movements of the scapula, you need to feel its lower corner. When the shoulder blade is motionless, this angle does not move. But as soon as she starts to move, he immediately changes position.

5. Why does the connection of the pelvic bones with the sacrum have low mobility, and why does the clavicle with the sternum have a movable joint?

In humans, the pelvic bones support the internal organs: stomach, intestines, excretory organs, etc. due to this they are inactive so as not to damage them, and also because the pelvis and sacrum are connected to each other by cartilage (semi-movable joint), and the sternum is connected to the clavicle joint (movable joint).

Why does the seemingly fixed connection of the pelvic bones with the sacrum still have little mobility? The elements of the pelvis are attached to each other using low-elastic ligaments; these structures allow the bones to diverge somewhat.

Pelvis as a functional unit

In order to figure out whether the pelvis should be connected to the sacrum using a movable joint, it is necessary to understand the functions and general structure of this part of the skeleton. The pelvis is formed in such a way that it has all types of joints:

1. Movable joint. It has the name of a true joint. First of all, this is the hip joint, connecting the limbs to the pelvis. Also, like most joints, it does not have a large angle of movement.
2. Fixed joint. These are joints that are formed with the help of tight ligaments. These include the sacroiliac joint, which is secured by several ligaments.
3. Transitional joint. Defined as something between a movable and immobile joint, it is called the symphysis. This is how the frontal bone is connected to other elements using cartilage tissue, in which there is a gap - the pubic connection.

The pubic symphysis is almost always motionless, it is secured by ligaments. Its transitional form will only play into the woman’s hands when the time for childbirth comes - in order to prevent the fetus from being injured, the ligaments will become more elastic during pregnancy, which will allow the child to pass through the birth canal more easily.

During the period of human growth, the pelvic bones undergo several phases - from the separation of the three bones (pubis, ilium and ischium), to their gradual fusion. Complete fusion into 2 pelvic or innominate bones is observed at the age of about 25 years. These bones are connected in a circle to other components of the skeleton.

Why is the connection of the pelvis and sacrum motionless?

The complex and non-standard structure of the pelvis is necessary for the implementation of all the functions with which the pelvis is endowed. It really has a lot of functions:

1. The pelvis connects the torso to the lower limbs. In order for a person to walk normally, sit down and perform other movements, it is this area that has true joints.
2. The pelvic cavity contains internal organs that protect the pelvic bones from impacts and other injuries.
3. Support and foundation. When walking or other movement, the entire body rests only on the pelvic bones. In addition, the pelvis is the basis for the spine.

It is precisely because support is necessary, and man is known as the only upright species of creatures, that nature has provided a fixed connection of the pelvis with the sacrum. The connection occurs in such a way that the sacrum, the beginning of the spine and the pelvis creates an axis that maintains balance.

The connection, including the sacroiliac joint and the sacrum with the pelvic bones, is carried out using several ligaments:

1. Iliopsoas. Connects the iliac crest and several vertebrae.
2. Sacrospinous. Attaches the ischium, the horns of the coccyx and the horns of the sacrum.
3. Sacrotuberous. Acts as a connection between the sacrum, coccyx and ischial tuberosity.

These ligaments are thin, formed into short bundles. The sacrum enters, wedges into the space between the two pelvic bones and serves as a closure of the pelvic ring. When moving, thanks to the strong ligamentous apparatus, it remains in place all the time.

This is a stationary joint, considered to be stationary only conditionally, since there is movement, especially in the area of ​​the iliopsoas ligament. However, the movement is minimal - all ligaments can move no more than 4°, as for the iliopsoas ligament - it can move up to 8-10°.

For reference! Mobility in the coccyx area is more pronounced in women due to the fact that it must deviate back during childbirth and fetal movements.

If this joint had greater mobility, upright posture, as well as the integrity of the pelvic ring, would be at risk. Since no movement is needed in this area, the connection is made using strong, short ligaments.

The anatomy of the hip joint, when examined carefully, is a rather complex structure. Moreover, the structure of the hip joint and pelvic bone can change greatly with age. For example, in infants, the structure of the hip joint changes as they mature and grow. Initially, the articulation of the pelvis and pelvic bone can be called immature, because the ligamentous apparatus of the hip joint, which is part of it, is excessively flexible and elastic. In addition, researchers have found that in infants the socket of the hip joint is denser. This underdevelopment then disappears in humans. The articulation area is located lateral to the gluteal region, below the crest of the ischium.

The main function performed by the articulation of bones is to support the weight of the body when static and dynamic loads are placed on it. In addition to this function, the joint takes an active part in maintaining the balance of loads exerted on the body while maintaining balance in the body.

The structure of the pelvic apparatus

The anatomy of the human pelvis is quite complex. The pelvis includes two innominate bones. They are conventionally called right-handed and left-handed (located to the right and left relative to the axis).

The pelvis is classified according to size and shape. If there is a diagram of the structure of the hip joint and pelvis at different ages, then you can clearly see on what principles the classification of articular joints is carried out. Until the age of 15, the hip system has three bones: the pubis, the ischium and the ilium. This underdevelopment in humans goes away over the years. These bone structures are conventionally called the innominate pelvic bone.

Bones and ligaments of the joint

The head of each femoral bone of the pelvis is connected to the adjacent bones by the human hip joint. The diagram shows that in the area of ​​the acetabulum there is an articulation of three bones with the help of cartilage. The acetabulum is the junction of the femur and pelvic bones. As we grow older, all three bones of the hip system come together. The head of the pelvic bone is carefully covered with elastic, smooth connective tissue of the hip joint.

Narrowing of the joint space may indicate significant changes in the structure and shape of the cartilage. With arthrosis, a slight narrowing of the joint space will be visible on the x-ray. This is the first sign, because... At this stage, restrictions in movements are not yet observed.

As the structure diagram shows, the bone closest to the spine is the ilium. Its head connects to the sacrum and two other bones of the hip apparatus. The bone itself has a rounded shape with two protrusions.

The structure of the ischium in the design of the hip apparatus is as follows: the main body is connected from above to the ilium and individual processes. In addition, the ischium connects to the pubis (its process, horizontal lobe). Inside this cavity, which is formed by these three bones, is the head of the femur.

The pubic bone of the hip apparatus consists of a main body and two branches. The branches form a cavity, which is covered by a membrane.

Pelvic arteries

The artery of the hip apparatus is called the common iliac. It branches into two vessels. This occurs due to the division of the aorta. So, where the articulation of the sacrum and the hip apparatus is located, the branches of the artery give rise to two more paired vessels that intertwine it.

Blood vessels supplying the pelvic joint

The external artery is the main vessel; it supplies blood to the lower extremities. In the area of ​​the hip joint, other branches of vessels depart from it, which pass further into the joints, muscles of the legs, abdomen and to the genitals. Then the vessel passes into the femoral artery, from which the following branches pass:

1. The deep femoral artery is the largest vessel, which is divided into the lateral and medial arteries. They bend around the thigh and conduct blood to the pelvis and thighs.
2. The epigastric superficial artery, which bends around the abdominal muscles in this place.
3. Artery near the ilium.
4. Genital arteries, which are external and supply the genitals with blood.
5. The inguinal arteries, which are responsible for the groin area, skin and lymph nodes in the area.

The second (internal) artery is located in the pelvis. The lumbar arteries, sacral, gluteal, umbilical, vas deferens, genital arteries and rectal arteries depart from it.

Pelvic joint

The structure of the pelvic joint is very complex. The articulation is formed by the head of the femur and the socket formed by the pelvic bones (acetabulum). The surface of the hip joint in the acetabulum is covered with a layer of cartilage tissue only in a certain area of ​​the hip joint. At the articulation site, the femur is covered with a thin layer of cartilage tissue. The hip joint connects its constituent bones into a single structure. Inside the cavity there is loose connective tissue. It is covered with a synovial bursa. At the edges of the cavity there are lips measuring 5 mm. They are formed from collagen connective fibers. Due to this, there are no voids between the bones, and the head of the femur fits tightly. The hip joint is the largest bone joint in the human musculoskeletal system. The hip bone, part of the joint of the same name, is the largest bone in the body.

Hip injuries have always been difficult to treat, so it is better to know the basics and try not to injure yourself. The pelvic joints are quite fragile due to their specific structure and the loads that are placed on the joint during life.

The hip joint capsule has a high level of structural strength. The capsule is attached to the pelvic bone behind and in front of the lips of the hip joint. As a result of this design, it turns out that the neck is almost completely located in the capsule of the hip joint. The iliopsoas muscle is attached to the capsule. The capsule in this place becomes thinner, so additional synovial fibers of the hip joint are most often formed.

This cavity contains the ligament of the femoral head. It consists of loose fibers, and is covered on top with synovial fibers of the connective tissue of the hip joint. This ligament also contains vessels that lead to the femur. The ligament can stretch quite easily, so its mechanical and protective value is not very great for the hip joint. The main function of this ligament is to connect the bones that make up the hip apparatus.

The iliac femoral ligament is considered the strongest not only among the ligaments that make up the hip joint, but also in the entire body as a whole. Its thickness can reach one centimeter. The ligament prevents the hip from fully internally rotating or extending.

The ischial femoral ligament can be considered less developed. It is much weaker; this ligament is located behind the hip joint. The anatomical location of this ligament is due to the fact that it provides stability to the body's hip apparatus when the femur is displaced inward.

The pubic femoral ligament is located at the bottom of the hip apparatus. This is a very thin bundle of connective fibers that does not allow hip abduction.

Injuries to the hip system mainly occur due to fractures and cracks of the bone in this area or due to problems with the ligaments or the entire hip joint in general. Wear of cartilage leads to many complications in movement.

Surgical intervention

Pelvic osteotomy is a surgical procedure to treat hip dysplasia. This pathological change can occur from birth and consists in the fact that the acetabulum of the hip joint is modified.

This can lead to the development of pelvic diseases, frequent subluxations, problems with the femur and gait disturbances. Osteotomy is aimed at creating additional bone structure of the hip joint, which will help fix the femur more firmly. Then no collateral damage will occur.

If something hurts after surgery, you need to be examined again. Osteotomy can only be performed after reaching the age of 10 years. But if arthritis develops, then an operation such as an osteotomy is prohibited.

Causes of pain

If your pelvis hurts, you should consult a doctor, because... violations can be of a very different nature. Modern doctors list a large list of possible causes of pain in the hip joint and pelvic bones. Most often, pain is caused by injuries and systematic diseases of the hip system.

Pain due to injury is the most common cause of pain in the hip joint and pelvic bones. If the pain does not subside within a week after a blow or fall, then you need to call a doctor. A neurologist and chiropractor will help in this process and prescribe a course of treatment. Falls and unsuccessful movements can cause fractures of the hip bones, cracks, and dislocations of the joint. In case of sharp and severe pain, it is necessary to protect the pelvis and lower limbs from movement, apply cold, and drink an anesthetic until a full diagnosis of the problem of the hip joint is established.

In systemic diseases, inflammation of the connective fibers occurs. This means that an infection has begun to develop in the body or it may be a symptom of another disease. Such pain can be caused by osteoarthritis, infectious arthritis and osteoarthritis. In addition, pain can be caused by disturbances in the blood vessels of the pelvic structure. Pain can also be caused by tumors in the joint.

It is better not to self-medicate. Based on the nature of the pain, it is difficult to make a diagnosis and prognosis, and some medications, on the contrary, can only cause harm. The pelvic complex is very complex, so you need to see a doctor.

If the anatomical elements of the hip joint are damaged, an early visit to a medical specialist is required in order to carry out rehabilitation measures, since long-standing injuries to this bone joint can cause a huge amount of trouble in the process of human life.

The pelvis is part of the human skeleton; it connects the legs to the torso. The pelvic bones form a girdle, which consists of two sections: the large and small pelvis. It produces a supporting function, so its shape is different from other bones of the skeleton. This bone is the largest in human anatomy.

Hip joint

Pelvic structure

It is not for nothing that the pelvis has such a structure, because its functioning is especially important. It consists of two innominate bones, the sacrum and the coccyx. The pelvic bones are connected using joints to form a ring, in the middle of which is the pelvic cavity.

Before the age of fifteen or sixteen, the pelvic bone consists of not one bone, but three. They are called “pubic”, “sciatic” and “iliac”. The connection occurs with the help of cartilage. Over time, the three bones fuse into one and continue to function as one.

The hip joint is formed by the articulation of the femur with the acetabulum of the pelvic bone. This area has a different structure in the two sexes - the pelvic bones in women are wider than in men, and the pelvis itself is lower.

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Functionality

The bones of the pelvic girdle perform two main functions:

1. musculoskeletal, because the load of the entire body goes most of all to the pelvis;
2. protective, because thanks to the pelvic bone, the organs that are located in this part of the body are protected.

It is not for nothing that the human skeleton has such a structure, so the pelvic bones merged into one strong one to serve as a support for the entire body. In the center is the trochanteric cavity; this bone has a lunate surface; it connects the femur with the pelvis. In its center is the acetabulum; this point is the main one, because the load is placed on it the most. This is where the three bones fuse together after adolescence.

Bones of the pelvic girdle

The pelvis plays one of the main roles in the movement of people. Thanks to this structure, a person walks upright, can maintain balance, and the load is distributed evenly.

During damage to the pelvic bone, fracture or other disease, motor function is immediately impaired. The spine also rests on this area of ​​the skeleton.

The pelvic girdle protects many organs. Behind the bones, which are highly durable, are the genitals, bladder, and part of the intestines. This protection is especially important during pregnancy. The combination of the sacrum with the pelvic bone occurs through joints that are located on the iliac and sacral parts of the pelvis. This type of connection is very strong, despite the relationship to the joints, because its movement is limited. Thanks to this, while carrying a child, the uterus will be maintained in the desired position.

Pelvis during pregnancy and childbirth

During pregnancy, changes occur in a woman's body, and most of all this concerns the pelvic bones.

In the early stages of excellent condition, metamorphoses are not yet noticeable. But as the fetus grows, the belly begins to grow. The expectant mother may begin to embrace discomfort as early as the sixth month.

Pain in this part of the skeleton is common during such a period. The biggest changes will be observed by the ninth month. After all, the pelvic bones begin to gradually prepare for the appearance of the unborn baby.

As a child increases in weight, it creates pressure on the pelvic bones and spine. If severe pain begins to bother you, it means that your body lacks vitamin D and calcium. Most likely, the doctor will prescribe a special vitamin complex and also tell you how to adjust your diet.

If the pain is tolerable, you can do the following to help alleviate the situation:

During pregnancy, changes occur in the pelvic bones

• there is no need to stand on your feet for a long time and additionally load the spine and pelvis;
• you cannot sit in one position, you should walk around a little and warm up, and the chair should have armrests;
• Do not sleep on a very hard bed;
• It’s worth reviewing your diet and introducing more foods that are rich in calcium (milk, cottage cheese, sesame seeds);
• there is no need to overeat, which will lead to excess weight and additional stress on the pelvis;
• wear a special bandage that will support the abdomen and reduce pressure on the pelvic bones and lower back.

Nature has designed the female body in such a way that it is specifically designed for the birth of children; the pelvis has a different structure from the male skeleton. It used to be that the pelvic bones could expand during childbirth, but this myth has been dispelled. If no complications arise, the baby passes through the pelvic girdle without problems.

A newborn, after birth, is examined by a pediatrician. Before the age of one month, a baby may be diagnosed with hip dysplasia. It can be treated with the help of massage courses and special diapers, which have good reviews.

Fractures of the pelvic bones

Such injuries are classified as severe skeletal injuries. Particular severity occurs due to large blood loss, possible damage to internal organs, as well as painful shock.

When the sacrum is fractured, the sacral nerve can be damaged, often causing urinary incontinence. X-rays, CT and MRI are used for diagnosis.

People get such injuries after falls, car accidents, being under the rubble of buildings or due to any other pressure. The most common injury to the pelvis is an acetabulum fracture. It accounts for 15% of all fractures of this type.

Symptoms of such fractures are deformation changes in the pelvic area, severe acute pain, hematoma and swelling. In thirty percent of victims, traumatic shock begins to develop. It is accompanied by heavy bleeding, compressive pain, as well as loss of sensitivity of some nerve endings.

During treatment, the patient is given an anesthetic complex and is also given fractional blood transfusions over two to three days. In order for the broken bones to heal, surgery is performed using Beler splints.

After fractures of this type, a long recovery of musculoskeletal function follows.

In elderly people, when osteochondral tissues lose their elasticity and their structure collapses, a dislocation or fracture of the femoral neck often occurs. This pathology is fraught with death. That is why it is recommended to carry out prevention and take medications containing chondroitin sulfate and glucosamine - active substances that promote bone tissue regeneration.

So, the pelvic bones perform a supporting and protective function. The pelvis, which connects the legs to the body, protects the internal organs and is also the basis of the locomotor system.

During pregnancy, women may experience pain in the pelvic ring. This indicates a calcium deficiency.

Fractures of the pelvic bones are one of the most severe types. They are often accompanied by damage to internal organs and heavy blood loss.