Anatomy and structure of the knee joint, muscles and ligaments that strengthen it. Knee joint: structure and main functions Muscles surrounding the knee joint

The basic organ of the human knee is the joint. That is why the anatomy of the knee joint is of great importance in order to have an idea about the structural features, features of treatment and recovery in case of problems. Indeed, in the entire musculoskeletal complex of a person, the knee joint is the most vulnerable part. It is surrounded by muscle tissue and ligaments. In this case, the knee joint consists of three main elements - this is the patella, femur and tibia.

The structure of the knee joint

The anatomy of the knee joint is such that friction between the bones is excluded. Due to this, the possible consequences of a blow are mitigated as much as possible. The cup protects the knee from external influences, which is why it so often gets injured and damaged. The joints themselves are also prone to a large number of diseases, especially if you give them constant stress and do not take care of them.

The anatomy of the human knee joint is quite complex compared to all other joints in the body. Also, its uniqueness lies in the fact that it is the largest. Thus, the human knee is special for two reasons at once - size and complexity. Because of this, treating the knee joint is always difficult.

Let's analyze the knee joint by its components. First, it is bones and muscles. These are the key parts of the entire knee, it is around them that the whole structure is formed. Second, the menisci. The mobility of the entire joint depends on them. Thirdly, these are nerve endings and a network of blood vessels. They revitalize the knee, making it sensitive to external influences. Fourth, these are ligaments and cartilage. They are the link between muscles and bones. It is they who have the main burden when walking and exercising.

Functions of the knee joint

In order for the knee to bend smoothly, there is smooth cartilage. It carefully covers the parts of the bones in those places where they are in contact with each other.

The interosseous space, in addition to cartilage, is filled with menisci. These are special layers that give a shock-absorbing effect under load, while the contact area is maximized. But if cartilage is present between all bones, then the menisci are only between the tibia and femur.

The synovial bursa also plays an important role in the knee joint. It covers the joint from the outside. It contains joint fluid, which lubricates cartilage, thus improving gliding and minimizing stress and friction in the knee joint. This fluid also has another function - for cartilage, it is also a nutrient, thanks to which they perform their unique functions.

Another important component of the knee joint that helps it perform its functions is the ligaments. They securely fix the bones at the junctions and provide a snug fit to the menisci. There are ligaments in most human joints, in the knee they are called cruciate, due to their shape. In the event of the slightest damage, it is extremely important to treat the ligaments. Plus, you don't even have to take medication. Enough tight fixing bandages and rest.

Bones of the knee joint

The anatomy of the bones of the knee joint includes only three bones. But mobility and, in general, the standard of human life depend on their integrity. The main protective function is performed by the patella, which covers the femur and tibia. The function of the knee joint is to connect these three components and provide them with maximum mobility, and it is also responsible for flexion and extension of the knee.

The anatomy of the knee joint and ligaments owes much of its integrity to the femur. It is she who bears the main burden. That is why it is located on top. The remaining tibia is located below and already takes on the load left from the femur.

No less important is the function of the patella, a special rounded bone, very similar to a triangle. It is often referred to as the patella.

The structure of the femur

The condyles play an important role in the femur. These are protrusions having the shape of a ball. They cover the lower surface of the femur. At the same time, they come into contact with the upper surface of the tibia.

The surface of the bone is called a plateau. It consists of two halves - lateral and amygdala.

Patella device

The knee joint plays an important role in human life. The structure, anatomy of this organ is what any doctor should know. Of great importance in it is the kneecap. By and large, its main purpose is to move along a specially designated chute. It is located between the femoral condyles, which we talked about above. They form this groove.

The patella, being the main protector of the knee from all kinds of damage, is itself prone to a large number of injuries. Therefore, at the slightest problem, immediate consultation with a specialist and treatment is required.

An equally important function is performed by cartilage, which covers the surfaces of adjacent bones. Its average thickness is about 6 millimeters. In children, of course, it is even less. Outwardly, the cartilage is white, smooth and very elastic.

Cartilage cope with the resulting friction, practically reducing it to nothing.

Functions of the knee ligaments

Without ligaments, it is impossible to imagine the knee joint. The structure, anatomy of this organ will be discussed below. The joint largely functions due to this connective tissue. However, it is very dense.

Ligaments are necessary for the interaction of the bones of the knee joint with each other. Special literal ligaments for this are located on the side of the joint, and collateral ligaments are located in the same area. They not only strengthen the entire joint as a whole, but also do not allow the bones to go sideways during especially strong physical exertion.

The most famous and injury-prone human ligaments are the cruciate. They connect the ends of the tibia and femur. It is thanks to the cruciate ligaments that these bones fit snugly together.

Another function of the cruciate ligaments is to prevent the movement of bones in directions unusual for them. The ligaments located in front and behind are also necessary so that the bones do not move relative to each other.

The topographic anatomy of the knee joint determines the important function of the ligaments - ensuring the mobility of the bones and at the same time monitoring their condition.

Menisci in the knee joint

In addition to the ligaments in the knee joint, there are other formations that are similar in structure and perform similar functions. These are the menisci. Their location is between the femur and tibia. In those places where they act from each side. Despite the fact that the menisci, cartilage and ligaments are very similar in appearance and perform similar functions, there is a fundamental difference between them. First of all, in the structure, as well as in the performance of specific tasks.

The menisci, like the patella, are subject to frequent injury and must be taken care of and treated promptly at the first sign of problems. If the meniscus is damaged, surgery may be required, up to and including surgery.

Meniscus functions

If you care about your health, it is important to know the structure of the human knee joint. The anatomy of this organ is not simple, but understanding what each of its components is responsible for will help you avoid serious health problems.

Menisci are required to perform two main functions. First, they maximize the area of ​​contact between the bones. Due to this, the load on each of them individually is reduced. The pressure per unit area of ​​the femur or tibia becomes less.

The second important function of the meniscus is to ensure the stability of the knee joint. In this case, the menisci provide invaluable assistance to the ligaments. In the event that the menisci do not perform any of these functions, it is urgent to contact a specialist for qualified help.

The anatomy of the knee joint is such that the menisci play one of the most important roles in it. These are flexible mats that behave as if ball-shaped bones descend on a flat surface covered with pillows. The pillow in this case performs the function of softening, repeating the shape of a spherical surface. So does the human meniscus.

The menisci act not only as soft and comfortable pads between the bones, they also fill the voids that could arise at the points of contact between the bones. The meniscus does not allow them to do this. This meniscus-filled space is located between the condyles and the tibia plate.

Only thanks to them it is possible to achieve a uniform distribution of the weight of a person over the entire area of ​​​​the tibial plateau. If there were no menisci, then all the weight would fall on only one point of the plateau, it would be much more difficult for human knees to bear it. Therefore, the main thing for which they are needed is to protect the joints from excessive loads.

How is the implementation of the second important function of the menisci - ensuring the stability of the joints? The fact is that they have a shape resembling a crescent moon. And at the same time different in thickness.

In its central part, the meniscus is much thinner than at the edges. This forms a kind of cavity, thanks to which the joints become stable. Also, the menisci can change their shape due to elasticity, so the joint does not lose its stability both in statics and in dynamics.

Muscles in the knee joint

The muscles of the knee joint, the anatomy of which is represented by two groups, also play a significant role. They are divided into extensor muscles and flexor muscles, each of which is responsible for a corresponding function.

The extensors are located in front of the femur. Due to them, a person has mastered upright posture, with their reduction, the knee joint straightens. The quadriceps muscle is important, its role is to extend the leg at the knee.

The flexor muscles are located at the back of the femur and are also important for joint function.

Nerves in the knee joint

The anatomy of the knee joint also includes the nerves that are responsible for delivering commands from the brain to certain muscle groups when they need to contract.

The largest nerve in the knee joint is the popliteal. It is located in its back. If the nerves are damaged, most often due to trauma, you should immediately consult a doctor.

The main popliteal nerve branches into the peroneal and tibial nerves. The first are located at the upper end of the fibula, the second - on the back of the lower leg.

Elements of the knee joint

There are many more elements without which it is impossible to imagine the knee joint. Anatomy (we presented the photo in the article) of this organ is studied in all medical educational institutions.

An important role is played by the circulatory system located in the knee joint. It lies in the vessels passing through the entire knee. In the back, they branch out in much the same way as the popliteal nerve does. In this part of the body, the two main blood vessels are a vein and an artery. To accurately identify them, they are called popliteal. The function of the artery is to supply the knee joint with fresh blood, the veins send the used blood back along the large

The human ankle joint is the reference point of the skeletal skeleton of the lower limb. It is on this articulation of a person that the weight of the body falls while walking, playing sports, running. The foot, unlike the knee joint, holds loads by weight, and not by movement, this is reflected in the features of its anatomy. The structure of the ankle joint of the leg and other parts of the foot is of no small clinical importance.

• Human foot anatomy
• Bundles
• muscles
• Achilles tendon
• blood supply
• Other joints of the ankle
• Functions
• Diagnostics

Arthritis

Injuries

Achilles tendon rupture

Human foot anatomy

Before considering the structure of different sections of the foot, it must be said that in this section of the leg, muscle elements, ligamentous structures and bones organically interact.

In this case, the bone skeleton of the foot is divided into phalanges of the fingers, metatarsus and tarsus parts. The bones of the tarsus are connected at the ankle joint with the elements of the lower leg.

In the tarsus, one of the largest bones is the talus. On the top is a ledge called a block. This element is connected from all sides to the tibia and fibula.

In the lateral elements of the articulation are bone outgrowths, which are called ankles. The outer is part of the fibula, and the inner is the tibia. Each joint surface of the bones has hyaline cartilage, which plays a shock-absorbing and nourishing role. The articulation is:

• According to the process of movement - biaxial.
• The shape is blocky.
• By structure - complex (more than 2 bones).

Bundles

Limitation of movements in the human joint, protection, retention of bone structures with each other are possible due to the presence of ligaments of the ankle joint of the leg. The description of these elements must begin with the fact that these structures in anatomy are divided into three groups. The first group includes fibers that connect the bones of the lower leg to each other:

• The inferior posterior ligament is the part that prevents the internal rotation of the leg bones.
• Interosseous ligament - the lower part of the membrane, which is stretched between the bones of the lower leg along its entire length.
• The transverse ligament is a small fibrous part that provides fixation of the foot from turning inward.
• Inferior anterior fibular ligament. The fibers of this part are directed from the outer ankle to the tibia and help keep the foot from turning outward.

In addition to the above functions of the fibers, they also provide fastening of the powerful tibia to the fragile fibula. The next group of human ligaments are the external lateral fibers:

• Calcaneal fibula.
• Posterior talus fibula.
• Anterior talus fibula.

These ligaments originate at the external fibula and diverge in different directions towards the parts of the tarsus, therefore they are generalized by such a term as the "deltoid ligament". The function of these structures is to reinforce the outer edge of the given part.

The third group are the lateral internal ligaments:

• Tibial heel.
• Tibial navicular.
• Traram posterior tibial.
• The talar anterior tibial.

Similar to the anatomy of the fiber groups described above, these ligaments keep the tarsal bone from moving and begin at the medial malleolus.

muscles

Additional fastening elements, movement in the articulation are achieved with the help of muscle elements that surround the ankle joint of the leg. Any muscle has a specific fixation point on the foot and its purpose, but structures can be grouped according to their main function.

The muscles that are involved in flexion are plantar, tibialis posterior, long flexors of the thumb, triceps. The long extensor of the thumb and the anterior tibialis muscle are responsible for the extension function.

The third group is called pronators - these fibers rotate the ankle joint inward towards the middle part. These muscles are long and short peroneal. Their antagonists are the peroneal anterior muscle, the long extensor of the thumb.

Achilles tendon

The ankle in the posterior region is fixed by the largest Achilles tendon in the human body. The articulation is formed by combining the soleus and gastrocnemius muscles in the lower part of the lower leg.

Stretched between the calcaneal tubercle and the muscular bellies, a powerful tendon has an important function during movement.

An important clinical point is the likelihood of sprains and ruptures of this structure. At the same time, in order to restore function, the traumatologist is obliged to conduct complex treatment.

blood supply

Metabolic processes, restoration of elements after injury and stress, the work of muscles in the joint is possible due to the special anatomy of the blood supply that surrounds the connection. The structure of the arteries of the ankle joint is similar to the scheme of blood supply to the knee joint of the leg.

The posterior and anterior peroneal and tibial arteries branch in the region of the inner and outer ankles and capture the joint from all sides. Due to this device of the arterial network, the normal operation of this anatomical part occurs.

Venous blood departs from this part through the internal and external networks, forming important connections: the tibial and saphenous internal veins.

Other joints of the ankle

The ankle connects the bones of the foot with the lower leg, but small parts of the lower limb are also connected to each other by small joints:

Such a complex anatomy of the human foot helps it maintain a balance between support function and leg mobility, which is important for a person to walk straight.

Functions

The structure of the ankle is primarily aimed at achieving the mobility that is required when walking. Due to the coordinated work in the muscle joint, it is possible to perform movement in two planes. In the frontal plane, the ankle joint performs extension and flexion. In the vertical axis, rotation can occur: in a small volume, outward and inward.

In addition, due to the soft tissues of this area, which preserves the integrity of the bone structures, movements are damped.

Diagnostics

In the ankle joint, the legs can undergo various pathologies. To visualize the defect, identify it, correctly establish the diagnosis, there are different diagnostic methods:

• ultrasound. To date, it is rarely used, because, unlike the knee joint, the cavity of the ankle joint is small. But this method is distinguished by the absence of a negative effect on the tissue, the speed of implementation, and the economy. It is possible to determine foreign bodies, edema and accumulation of blood in the articular bag, to visualize the ligaments.
• Athroscopy. A low-traumatic and minimally invasive procedure, including the introduction of a video camera into the capsule. The doctor will be able to look at the surface of the bag with his own eyes and identify the focus of the disease.
• Radiography. The most affordable and cost-effective survey option. In different projections, images of the ankle joint are taken, where a tumor, dislocation, fracture and other processes can be detected.
• MRI. This procedure is better than any other will determine the condition of the Achilles tendon, ligaments, articular cartilage. The method is quite expensive, but the most effective.
• CT scan. This method is used to assess the state of the articular skeletal system. With arthrosis, neoplasms, fractures, this method is the most accurate in terms of diagnosis.

Instrumental methods are supplemented by the results of laboratory tests and medical examination, based on this information, the specialist determines the diagnosis.

Pathology of the articulation of the ankle joint

Alas, even a strong ankle is prone to injury and the appearance of diseases. The most common diseases of the ankle joint are:

• Arthritis.
• Osteoarthritis.
• Achilles tendon ruptures.
• Injuries.

How to identify the disease? What to do and which doctor to contact? It is necessary to understand all the listed diseases.

With this disease, due to a lack of calcium, traumatization, and frequent overstrain, dystrophy of cartilage structures and bones develops. Over time, outgrowths are formed on the bones - osteophytes, which violate the range of motion.

The disease is manifested by mechanical pain. This means that the symptoms increase in the evening, decrease at rest, and increase after exercise. Stiffness in the morning is absent or short-term. There is a gradual decrease in the mobility of the ankle.

With these signs, you need to contact a therapist. With the development of complications, he will send for a consultation with another doctor.

Arthritis

Inflammatory processes of the articulation can occur during the development of rheumatoid arthritis or infection in the cavity. Also, the ankle can become inflamed with gout as a result of the deposition of uric acid salts.

The disease manifests itself as pain in the joint in the morning and by the end of the night. When moving, the pain subsides. Symptoms are removed with the help of anti-inflammatory drugs (Diclofenac, Nise, Ibuprofen), as well as after applying gels and ointments to the ankle joint. It is also possible to determine the pathology by the simultaneous damage to the joints of the hand and knee joint.

Rheumatologists deal with this disease, they recommend basic drugs to eliminate the symptoms of the disease. Each disease has its own drugs designed to stop the inflammatory process.

The most important thing is to distinguish infectious arthritis from other causes. As a rule, it is manifested by severe symptoms with edematous syndrome and intense pain. Pus collects in the joint cavity. Often, hospitalization of the patient is necessary, bed rest is required, treatment is with antibiotics.

Injuries

During direct injury to the ankle at work, in an accident, in sports, various tissues of the joint can be damaged. Damage can cause a violation of the integrity of the tendons, rupture of ligaments, fracture of bones.

Common signs are: swelling, pain after injury, inability to step on the lower limb, decreased mobility.

After an ankle injury, it is necessary to ensure the rest of the limb, apply ice to this place, then consult a doctor. The traumatologist, after examination and research, will prescribe a set of treatment procedures.

As a rule, therapy includes immobilization (immobilization of the joint), as well as the appointment of painkillers and anti-inflammatory drugs. Sometimes surgery may be required, it can be performed using arthroscopy or in the classical way.

Achilles tendon rupture

With a direct blow to the back of the ankle joint, with a fall on the leg, during sports loads, a rupture of the Achilles tendon can occur. In this case, a person cannot straighten the foot, stand on his toes. In the area of ​​​​damage to the leg, blood accumulates, edema is formed. Joint movements are very painful.

In the end, I would like to note that the control of the leg muscles occurs due to the nervous system. If the joints and muscles are not loaded, they gradually atrophy, and when the joints work for a long time without rest, their fatigue inevitably comes. After rest, the joints of the legs come in tone, and their performance is restored. Therefore, doctors recommend more frequent breaks between hard physical work.

Human bones are interconnected by means of joints, there are many of them, but the most complex, the most vulnerable is the knee joint. To form a joint, three bones form a complex relationship; the first, largest is the femur, the second is the tibia, and the third is the patella, the largest is the sesamoid bone. The patella is an additional lever that helps to make complex movements.

So what are the secrets structure of the knee joint, which acting forces influence him, including during the run, remains to be figured out. Despite the fact that its anatomy is complex, you only need to understand what is where, what role it plays if treatment is indicated.

General subtleties

In general, the joint is formed by two joints: the first, main, femoral-tibial, the second is formed by the femur and patella. The joint is complex, it is condylar in type. The joint moves in three mutually perpendicular planes, the first, which is also the most important, is the sagittal one, in which flexion and extension occur, which is carried out in the range from 140 to 145 degrees.

In the frontal plane, there is abduction, adduction, it is insignificant, it is only 5 degrees. In the horizontal plane, rotation occurs inside, outside, small movements are possible in a bent position. From a normal or neutral, bent position, rotation is possible no more than 15-20 degrees.
Additionally, there are two more types of movements, which are represented by sliding, rolling of the articular surfaces of the condyles of the tibia in relation to the femur, occur in front, back, and vice versa.

Biomechanics

The anatomy of the joint is impossible without an understanding of biomechanics, the treatment is based on this. It is complex, its essence lies in the simultaneous movement in several planes. If a person tries to straighten the leg from 90 to 180 degrees, then due to the ligaments, there is a rotation, displacement in front or to the other side of any part of the tibial plateau.

The structure is such that the condyles of both bones are not ideal in relation to each other, so the range of motion increases significantly. Stabilization occurs due to the presence of many ligaments, complemented by adjacent muscles.
Inside the cavity there are menisci, strengthening occurs due to the capsular-ligamentous apparatus, which is covered on top with a muscle-tendon complex.

Soft tissue structures

This is a complex of soft tissues, which, performing a specific function, provide range of motion. These include a large number of formations that have their own structure. In general, children's and adult joints do not differ in their structure.

menisci

These formations consist of connective tissue cartilage, roughly speaking, this is a gasket located between the smooth surfaces of the condyles of the femur, tibia. Their anatomy is such that they contribute to the elimination of incongruence. In addition, their structure involves depreciation, redistribution of the load on the entire surface of the bones. Due to all of the above, the human knee is stabilized, the synovial fluid evenly moves through the joint.

Along their periphery, the menisci are tightly connected to the capsule with the help of ligaments. They differ in strength, because the maximum load falls on the periphery.
During movement, the menisci move along the surface of the tibial plateau, this process does not occur during rupture, therefore, treatment is required. The menisci are reinforced with collateral, cruciate ligaments.

The free edge of the meniscus faces the center, the children's joint, unlike the adult, contains blood vessels. The menisci of an adult have them only along the periphery, which is no more than 1/4. The capsule surrounds everything, which has folds, bags, liquid is produced in them. It is nutrition, a lubricant for cartilage, its total amount does not exceed a teaspoon. Folds replace the cavities of the knee, create additional cushioning.

Ligament apparatus

In the cavity of the knee joint there are formations - cruciate, paired ligaments. They are separated from the cavity with the help of the synovial membrane. Thickness 10 mm, length 35 mm. The anatomy of the human anterior cruciate ligaments is such that they begin with a wide base on the inner or medial surface of the femoral condyle located outwards. Further, their structure differs in that they go from top to bottom inwards, attaching to the anterior surface of the intercondylar eminence on the tibia.

The structure of the ligaments is based on a large number of fibers, which, when combined, form two main bundles. During movement, the load is experienced by each individual bundle of ligaments. Thus, not only the muscles are involved in strengthening the joint, preventing dislocation of the bones. Normally, the anterior cruciate ligament, by its tension, prevents even minimal subluxation of the external condyle, the plateau of the tibia, when the joint is in the most vulnerable position.

The posterior cruciate ligament is 15 mm thick and up to 30 mm long. The beginning takes in the anterior part of the inner condyle of the thigh, following down, outward, is attached to the posterior surface of the intercondylar eminence behind the tuberosity. The structure of the posterior ligament involves the interweaving of part of the fibers into the joint capsule.

The posterior cruciate ligament does not allow the tibia to move backwards, its hyperextension. When a ligament is ruptured in a person, this kind of movement becomes possible, the degree of rupture determines the treatment. The bundle also includes two bundles of fibers.

Extra-articular ligaments

On the inside, the knee is strengthened not only by muscles, but also by the internal collateral ligament. It contains two portions - superficial, deep. The first portion plays the role of a joint stabilizer, consisting of long fibers that fan out from the inner condyle of the thigh, gradually pass to the tibia. The second portion is formed by short fibers, partially woven into the area of ​​the menisci of the human joint. With a complete rupture of the ligament, the treatment is reduced to surgery.

On the outer surface, the human joint is strengthened by external or lateral collateral ligaments. Partially, the fibers of this ligament pass to the back surface, where they participate in additional strengthening. A child's joint contains more elastic fibers in the ligaments of the joint.

muscles

In dynamic terms, in addition to ligaments, muscles are involved in stabilizing the joint. They surround the joint on both sides, complicating its structure. With a partial rupture, the muscles of the knee in a person contribute to its additional stabilization. All muscles have their strength. But the most powerful is the quadriceps, which is involved in the formation of the patellar ligaments.

With pathology, the muscles, especially the quadriceps, begin to atrophy, strength decreases. During the rehabilitation period, treatment is aimed at restoring its function, as the most important.

When it is necessary to repair the posterior instability of the knee, the main treatment is to strengthen the joint after damage to any part of the posterior cruciate ligament. The composition of the posterior muscle group includes semimembranosus, semitendinosus, tender, which are located on the inside of a person, the biceps is located on the outer surface of the thigh.

Norm and pathology of the knee

Understanding the processes occurring in the joint optimizes the treatment, making it more effective. It is not enough to know the structure of a human joint, how it functions matters. An adult, children's joint has articular surfaces that are covered with highly differentiated hyaline cartilage. It consists of chondrocytes, collagen fibers, ground substance, growth layer.
The load that falls on the cartilage is evenly distributed between all components. The structure according to this principle allows you to transfer the load by pressure or shearing nature.

The structure of the knee can be significantly affected by an injury, the mechanism of which largely depends on the treatment. Cartilage can be damaged as a result of excessive impact during sudden braking at the moment of rotation. When the ligaments are damaged, the joint becomes unstable, it begins to shift to the sides. An additional factor complicating treatment can be hemarthrosis, in which blood accumulates in the cavity knee joint. The dead cells lead to the release of a large number of lysosomal enzymes, which ultimately leads to the destruction of joint structures.

Basically, in the joint, as a result of external causes, its cartilage is damaged. The degree of damage depends on the strength, duration of the damaging factor. Cracks appear, which are the gates for further destruction of collagen fibers. Vessels sprout from any part of the bone, they lead to a decrease in restorative capacity. The bone is also subject to destruction processes.

The joint has a complex macroscopic, microscopic structure, function, understanding of which helps to treat it correctly.

2016-06-10

How the human foot works: anatomy, “weak points”, possible diseases and their prevention

The feet are parts of the lower limb that perform very important functions, providing support for the body when standing and walking. Together with other parts of the body, they are directly involved in the movement of the body in space. At the same time, this part of the lower extremities performs spring functions, providing mitigation of shocks when walking, running, jumping, as well as balancing functions - regulating a person's posture during movements. All these functions performed were the reason for the special anatomy of the feet.

The foot is a very complex part of the human body, consisting of 26 bones connected by 33 joints and strengthened by numerous muscles, ligaments, tendons and cartilage.

The 26 bones of the foot are conventionally divided into 3 sections: fingers, metatarsus and tarsus.

toes

Each toe consists of 3 phalanges. The only exception is the thumb or first finger, which has only 2 phalanges. Quite often, the phalanges of the little finger grow together, as a result of which it also consists of 2 phalanges.

The phalanges that are connected to the metatarsal bones of the foot are called the proximal, followed by the middle, and then the distal. The bones that form the fingers have short bodies.

At the base of the thumb on the plantar side there are additional sesamoid bones that increase the transverse arching of the metatarsus.

Metatarsus

This part of the foot consists of 5 short tubular metatarsal bones. Each of them consists of a trihedral body, base and head. The first metatarsal is the thickest and the second is the longest.

The heads of these bones serve to connect with the proximal phalanges, and the bases - with the bones of the tarsus. In addition, the lateral articular surfaces of the base of the metatarsal bones are interconnected.

The area of ​​the head of the first metatarsal bone is an active participant in the development of hallux valgus deformity of the big toe. During this process, a bony outgrowth develops on the outer edge of the metatarsal bone, which compresses the tissues and deforms the joint, resulting in severe pain and gait disturbance.

In addition, it is the first metatarsophalangeal joint that is most susceptible to arthrosis.

Tarsus

This section of the foot contains the largest number of diverse bones, which are located in 2 rows: proximal and distal.

The proximal row consists of the talus and calcaneus. The distal row consists of 3 cuneiform bones, the cuboid and the navicular.

In the structure of the talus, the body, neck and head are distinguished. It is this bone that connects the foot with the bones of the lower leg into one common mechanism. This joint is called the ankle joint.

The calcaneus is located behind and below the talus. This is the largest bone of the foot, consisting of a body and a tubercle. The calcaneus is united with the talus from above and with the cuboid bone with its anterior part. In some cases, a spike-like growth known as a "calcaneal spur" may develop on the heel bone. This is accompanied by severe pain and impaired gait.

The cuboid bone forms the outer edge of the foot. It is articulated with the 4th and 5th metatarsal bones, calcaneus, external cuneiform and navicular bones. Below it is a groove with a tendon of the peroneal muscle.

The navicular bone forms the inner side of the foot. It connects to the talus, sphenoid and cuboid bones.

The sphenoid bones (lateral, medial and intermediate) are located in front of the navicular bone and are connected to it. They also connect to the metatarsal bones and to each other.

Foot joints

The bones of the foot are interconnected by joints that provide its mobility.

One of the main joints of the foot is the ankle joint. It connects the foot to the lower leg. This joint has a block-like structure and is formed by the articulation of the talus and the bones of the lower leg. The ankle is securely reinforced with ligaments on all sides.

The ankle provides plantar and dorsiflexion (movement of the foot around the transverse axis).

Damage to this joint causes severe pain. Because of this, movement becomes difficult or even impossible. In this case, the weight of the body is transferred to a healthy leg, resulting in lameness. If you do not start timely treatment of the problem, then persistent violations of the mechanics of movement of both limbs are possible.

In the area of ​​\u200b\u200bthis joint, sprains and ruptures of the ligaments quite often occur. Synovitis of the ankle joint may also develop as a result of a violation of its pronation.

subtalar joint

No less important is the subtalar joint, which is formed by the calcaneus and talus. This joint has a cylindrical, slightly spiral-shaped structure. It allows the foot to turn inward and outward (pronation). Around the joint there is a thin capsule and small ligaments.

If the pronation of this joint is violated, the foot receives additional loads in the performance of its functions, which is fraught with dislocations and sprains of the ligaments.

wedge-navicular joint

This joint is on a par with the subtalar joint in importance, since they can compensate for the dysfunction of each other. If such compensation is observed for a long time, then the joints wear out much faster, which leads to their pathologies.

Talocalcaneal-navicular joint

From the name of this joint, it is clear which bones of the foot form it. This joint has a spherical structure and provides supination and pronation of the foot.

Tarsus-metatarsal joints

These joints form the solid foundation of the foot, as they are practically immobile due to the reinforcement of numerous ligaments. They are formed by the union of the metatarsal bones with the cuneiform and cuboid bones.

Metatarsophalangeal joints

These ball joints have little mobility and provide extensor and flexion movements of the fingers. They are formed by the bases of the proximal phalanges of the fingers and the heads of the metatarsal bones.

Due to the fact that the joint formed by the phalanx of the thumb and the head of the first metatarsal bone experiences the greatest load from body weight, it is most susceptible to a variety of pathologies. So it is this joint that is subject to gout, arthritis, sciatica, etc.

Interphalangeal joints

These joints provide connection between the phalanges of the fingers. They have a blocky structure and are involved in flexion and extension of the fingers.

Arch of the foot

The foot absorbs all the loads while running, jumping, walking thanks to a special arched structure. There are 2 arches of the foot - longitudinal and transverse. The longitudinal arch contributes to the fact that the foot rests on the surface not with the entire area, but only with the heads of the metatarsal bones and the calcaneal tubercle.

If the normal functioning of the ligaments and muscles of the foot is disturbed, the shape of the foot changes with a decrease in its arches. This leads to such a disease as flat feet. In this case, the foot loses its spring functions and the spine and other joints of the leg receive the load during movement. This leads to faster "wear" of the joints and spine, the appearance of pain and associated diseases.

Foot muscles

The movement of the foot is provided by 19 muscles located in the lower part of the leg. There are 3 muscle groups on the sole. One group is responsible for the mobility of the thumb, the second - for the mobility of the little finger, and the third - for the movements of all the toes. The fibers of these muscles are directly involved in maintaining the arches of the foot, and also provide spring functions.

The dorsum of the foot is made up of 2 muscles that are also involved in toe movement.

All other muscles that are attached to the bones of the foot, but start from the bones of the lower leg, belong to the muscles of the lower leg, although they take part in the movements of the foot.

With overstrain or strong relaxation of the muscles, it is possible to change the position of the bones and the reliability of the joints of the foot. As a result, various pathological conditions can occur.

Bundles

As you know, ligaments are inelastic, thick, flexible fibers that surround and support joints. With blows and leg injuries, pain and swelling most often provoke stretched or torn ligaments.

Tendons

Tendons are strong, elastic fibers that attach muscles to bones. When the muscles are stretched to the limit, it is the tendons that take on the stretching force. If such excessive stretching occurs, then inflammation of the tendons called tendonitis.

Blood vessels

The foot is powered by 2 main arteries: the posterior tibial artery and the dorsal artery of the foot. They split into smaller arteries and saturate the tissues of the foot with oxygen. Veins carry blood back to the heart. they are connected to the arteries by small capillaries. Among the veins are superficial and deep. The longest vein in the body originates at the big toe and is called the great saphenous vein of the leg.

Due to the fact that the blood vessels of the foot are the most distant, it is in them that circulatory disorders most often occur. This can lead to arteriosclerosis, atherosclerosis, varicose veins, swelling of the legs, etc.

Nerves

Of course, the functioning of the foot is impossible without nerves. Here are the main 4 nerves: gastrocnemius, posterior tibial, deep peroneal and superficial peroneal.

Often it is in this section of the legs that compression and infringement of the nerves occur.

Foot diseases

Such a complex structure and heavy loads that fall on them daily lead to their frequent diseases. All people are at risk of their occurrence, regardless of age and gender. But most of all, athletes and people whose work involves large constant loads on the legs are prone to foot diseases.

Foot diseases occur with severe symptoms and pain syndrome, therefore they cause a lot of inconvenience and discomfort. There are a huge number of them. Here are just a few of the most common ones: flat feet, arthritis, arthrosis, heel spurs, plantar fasciitis, bursitis, metatarsal deformities, dislocations, sprains, algodystrophy, bone fractures, osteochondropathy, tendonitis, soft tissue inflammation, hooked toes , calluses, lesions of blood vessels, pinched nerves and many others.

Disease prevention

It is much easier to prevent the development of the disease than to treat it later. Therefore, preventive recommendations will not interfere with anyone:

• it is necessary to provide systematic hygienic procedures for the feet;
• shoes should be selected comfortable, made from natural materials;
• try to wear high heels as little as possible;
• strengthen the muscles of the foot with the help of special exercises;
• it is advisable to use special orthopedic insoles;
• sports activities can only be carried out in specially designed shoes.

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The human skeleton is complex. Each element performs a specific function, responsible for normal life. Thus, the area of ​​the knees, including bone tissue, ligaments, nerves, joints, is responsible for the mobility of the limbs. Damage to at least one component can cause limited movement, or complete immobility. Therefore, it is so important to know the anatomy of the knee joint and ligaments in order to be able to recognize the signs of an impending disease and start treatment in time.

Elbow elements

The main constituent parts of the knee:

1. large bones with muscles that form the entire structure of the knee region;
2. menisci, thanks to which the joint moves;
3. nerves and blood vessels are responsible for sensitivity and reaction to various stimuli;
4. cartilage ligaments connect bones and muscles. These elements account for the main load of the knee region.

The anatomy of the knee joint is very complex, and makes it difficult to treat this area in case of various diseases. To make it easier to understand the anatomy of this important part of the skeleton, we propose to consider the structure of the knee joint in pictures, and get acquainted with each constituent element of the knee separately.

bone area

Let's figure out which bones are part of the knee:

The anatomy of the structure of the knee joint is such that its constituent bones are covered with cartilage. Cartilage tissue is designed to reduce the load on bone tissue during movement (the bones do not rub against each other).

According to the anatomy of the knee joint, bags filled with synovial fluid serve as a barrier against abrasion for the patella. The purpose of the bags is also to help the muscles while walking.

Muscle

The knee area is equipped with two groups of muscles responsible for flexion and extension of the limbs.

The extensors are in front of the femur. These muscles are responsible for motor activity, during their work the knee joint is able to straighten.

The flexors are located behind the thigh and knee region. With the contraction of this type of muscle, the limb can bend at the knee.

menisci

Let us turn again to the anatomy of the knee joint in pictures, where you can see in detail the location of the elements.

The menisci are located between the condyles and the plane of the tibia. Their purpose is to distribute the load from the femur to the tibia.

If any damage occurs to the menisci, or they have to be removed during surgery, then irreversible changes in the cartilage tissues may develop.

In the central section, the menisci are much thinner than in the peripheral. Due to this, a cavity of small depth is formed on the surface of the tibia, evenly distributing the load.

Nerves of the knee

The dorsal surface of the knee is equipped with popliteal nerve endings, which simultaneously provide sensitivity to the lower leg and foot.

Rising slightly above the knee joint, the popliteal nerve is divided into two types: tibial, peroneal. The first is located on the plane of the lower leg (back part), the second goes to its front region. With injuries to the knee area (such is the anatomy of the structure), both nerves are at risk (they can get damaged).

Blood vessels

Large vessels include the popliteal artery and the popliteal vein. Both blood vessels are located on the back plane of the knee.

The task of these vessels is to supply blood to the lower leg and foot. The artery carries the flow of nutrients peripherally, the popliteal vein - towards the direction of the heart.

The artery is also divided into the following vessels that carry blood:

• upper lateral, which is divided into even more well-aimed vessels;
• superior medial (above the medial condyle);
• middle knee, feeding the joint capsule;
• lower, knee literal;
• inferior, knee medial.

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• large saphenous, which flows into a large femoral vein;
• small subcutaneous, starting from the back of the foot. Further, the vein ascends to the popliteal fossa, where it merges, forming the popliteal fossa.

Ligaments and cartilage

Consider the anatomy of the ligaments of the knee joint - the connective tissue of the knee region. The function of ligaments is to connect and strengthen the bones that form the joint. Ligaments are divided into two types - extracapsular and intracapsular. Both types are divided into varieties that perform certain functions:

See what the anatomy of the knee joint is in the photo attached below.

The cartilage in the knee serves as a shock absorber for any movement. The joint constantly experiences friction while walking. But, the cartilage tissue remains elastic, smooth, despite heavy loads. Cartilage ends all the articular bones involved in movement and in contact with each other. Synovial fluid is a nutrient medium for cartilage tissue and maintaining its shock-absorbing properties.

Liquid capsule

The purpose of the joint capsule is protection. From the inside, the site is filled with synovial fluid, so that the joint can move without damaging the cartilage tissue.

Synovial fluid not only protects the cartilage, but also serves as a nutrient medium for it. The fluid also serves as a barrier to various inflammatory processes, preventing them from penetrating into the joint cavity. You can see the full structure of the knee joint in the video attached below.

Diseases in the knee area

Looking at the structure of the human knee joint and its diseases, we can divide them into two groups:

• arthritis, accompanied by various inflammatory processes;
• arthrosis, when there is a deformation of the tissues of the joint.

Diseases of the knee area occur for the following reasons:

1. injuries of varying severity with damage to the ligaments;
2. inflammatory processes in the meniscus or its removal;
3. fractures of the articular part of the knees;
4. hemorrhages in the knee area.

If there is pain when feeling the knees, swelling appears - be sure to contact the specialists for advice, diagnosis and treatment. It is important to diagnose the disease of the knee joint as soon as possible, so as not to lead to surgery and a long recovery period.

The beginning disease of the articular part may practically not manifest itself. Pain is not always felt, but only during exertion. Therefore, you should listen more carefully to the most insignificant changes, sensations in your body.

One of the clear signs of a disease of the knee joint is limited walking, a feeling of stiffness in the knee region. This happens when the joint cavity begins to accumulate a large amount of synovial fluid. The manifestations of the disease are as follows:

• the volume of the knee increases;
• swelling appears;
• it is difficult to bend, unbend the knee;
• with any, even minor loads on the limb, severe pain is felt.

Only a doctor can carry out diagnostic measures. Don't try to get rid of accumulated joint fluid yourself. The main thing is to prevent synovial fluid from entering the articular cavity.

The anatomy of the knee ligaments is such that they can be torn in case of injury. When the ligaments are torn, swelling appears in the popliteal part (fossa), instability and pain in the limb are felt.

In addition to visual signs, a gap signals itself with a crunchy, sharp pain. The first thing to do in such a situation is to stop moving (there is a loss of stability), ask for help. You can’t move on your own, because with a ligament injury, even your own weight will be a heavy load on the limbs.

After various knee injuries, bursitis, an inflammatory process of sacs filled with fluid, can develop. The fluid is designed to improve gliding between tendons and ligaments. Bursitis is manifested by constant pain, swelling, swelling, swelling of the knee joint. In rare cases, bursitis leads to a feverish condition.

Getting acquainted with the anatomy of the human knee joint, it is clear that the patella is one of the most vulnerable areas. It can shift - take a perpendicular position instead of a natural position. The triangular bone (the base of the patella) slips out of its normal place. With an injury, severe pain occurs, and then swelling of the knee.

After recovery, you should be aware that the displacement of the patella can be repeated more than once. With each subsequent injury, the pain becomes stronger. It is important to follow medical prescriptions and preventive measures during the recovery period in order to avoid re-injury.

Diseases of the knee joints affect not only adults, but also children. Adolescents involved in professional sports often injure their knee joints during high-impact workouts. As a result, Schlatter's disease manifests itself - inflammation of the tuberosity of the tibia. Signs of the disease:

• pain under the kneecap;
• the formation of a tumor in the region of the tibia;
• persistent pain even at rest.

The feeling of discomfort in Schlatter's disease, in some situations, disappears only when a teenager grows up.

In addition to diseases of the knee region resulting from injuries, there are chronic diseases:

• arthritis. It has many varieties, one of which is rheumatoid arthritis, accompanied by constant stiffness when moving;
• osteoporosis(wear and tear of cartilage tissue);
• gout(swelling of the knee area);
• chondromalacia kneecap when the pain affects the front of the knee.

The listed diseases are caused by a lot of weight, permanent or chronic injuries, heavy loads, age-related changes, professional sports, insufficient elasticity and flexibility of muscles.

Diagnostic measures

To diagnose the disease in the knee area, various methods are used. The anatomy of the knee joint is clearly visible on MRI. The method allows you to see accurate images of the tissues of the joint.

The use of MRI makes it possible to follow all the changes in the physiological plan that take place in the joints, to see the deformation that has occurred in the tissues.

This is a painless procedure with no contraindications. Thanks to the technique, an accurate diagnosis is made, it is possible to diagnose the smallest changes and injuries of the knee joint at the very beginning of the disease.

Ultrasound is also often used to determine changes in the anatomy of the knee joint. The diagnostic procedure is prescribed in situations:

• the presence of neoplasms on the articular bones (to determine their nature);
• in inflammatory processes;
• ligament ruptures;
• if the menisci or patella are damaged.

During diagnostics, the knee area is scanned in different projections, which makes it possible to examine the damage to the joint. The procedure does not require preliminary preparation, is painless and takes a little time (about 20 minutes). According to the results of the examination of the knee joint with the help of ultrasound, the doctor diagnoses the disease.

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The human knee is a unique joint capable of performing complex spatial movements. No four-legged animal has such a mobile and at the same time stable connection. The knee acquired such complex anatomical features and functional features in the process of evolution, from the moment a person became upright. Consider the structure of the human knee joint in order to better understand how it works.

Knee joint: anatomy and functions

The knee joint consists of:

• from two tubular bones (femur and tibia) and one sesamoid bone (patella) (the fibula of the lower leg is not included in the joint);
• seven external and three intra-articular ligaments;
• lateral and medial menisci;
• articular (synovial) capsule;
• several synovial bags (burs).

Main bones of the knee joint

The articular surfaces of both tubular bones (epiphyses) have two condyles - terminal extensions. One of them is internal (medial), the other condyle is external (lateral). The condyles of the thigh have a convex shape, between them there is a depression. Accordingly, the condyles of the tibia are concave in shape with an elevation in the middle. Thus, an ideal condylar lock of the epiphyses is formed. The surfaces of the condyles are covered with a smooth cartilaginous layer (hyaline cartilage), which ensures smooth, unhindered sliding in the joint.

The articulation surfaces do not adjoin tightly to each other: between them there is a joint space, which is clearly visible on radiography.

The tubular bones of the joint are connected by four ligaments - two lateral external (lateral and medial) and two internal (anterior and posterior cruciate ligaments).

The patella (synonymous with the patella) is located in front of the knee. Its role is twofold: it must protect the knee as much as possible and at the same time ensure its full mobility. The need for a patella and complicates the structure of the knee:

The patella is suspended with the help of three ligaments - one's own and two supporting ones. This ensures his freedom and at the same time keeps him in an anatomically correct position.

The inner surface of the patella, like other articular surfaces, is covered with hyaline cartilage.

Articular capsule of the knee

The joint capsule is a soft-tissue elastic two-layer shell, a bag in which the joint moves.

Its upper layer consists of fibrous tissue, and the inner one of the synovial membrane. The synovial membrane is permeated with a network of blood vessels through which important substances enter the joint. In addition, the shell itself produces a special fluid (synovia), which contains:

• chondroitin sulfate (the main component of cartilage);
• glycosaminoglycan (hyaluronic acid), which increases viscosity, due to which the synovium turns into a lubricant for the joints.

Not from the bones, but from the synovial membrane, degenerative-dystrophic processes in the joints often begin. She is directly involved in the pathogenesis of arthrosis. Pathologies of the synovial membrane, congenital or acquired, impoverish the synovium, giving rise to a deficiency of the main components in it, which disrupts the process of cartilage regeneration, leads to difficult movements and a crunch in the joints.

The articular capsule forms numerous inversions and pockets, which increases its volume, allows you to bypass all the elements of the joint and promotes better circulation of the synovium.

In addition to internal pockets, in the knee area there are many superficial and deep bags (burs) located between the tendons, under them and not far from them. More about bursas in.

Ligaments of the knee

The anatomy of the knee joint is represented by nine ligaments, each of which has its own purpose.

The general role of the ligaments is the reliable stability of the joint: none of its parts during flexion, extension, abduction, adduction or rotation should not go beyond the allowable limit. The margin of safety of the ligament allows us to exceed these limits, but thanks to our nervous system, which regulates all movements of the ODS, at the moment of a dangerous approach to the anatomical barrier, a sharp pain occurs in the joint. If this were not the case, the person would constantly injure himself. If the applied external force exceeds the margin of safety of the ligament, a rupture occurs in it.

Why are sports injuries so common? During the competition, a lot of adrenaline is released into the athlete's blood, and he stops just feeling pain, and may not even notice that a ligament or meniscus has torn.

Ligaments of the femur and tibia

The femur and tibia are strengthened:

• two lateral (collateral) ligaments - external (lateral) and internal (medial);
• anterior sacral ligament (ACL);
• posterior sacral ligament (PCL).

external collateral ligament also called fibular: it starts from the epicondyle of the femur and goes to the head of the m / b * bone. It does not connect to the joint capsule.

Internal collateral ligament(synonym: tibial) connects the inner epicondyle of the femur with the inner surface of the b / b * bone. It is wider and more powerful than the outer one, covers the joint capsule, connecting with it in front and behind, and is attached to the medial meniscus.

The role of the collateral ligaments is to limit lateral flexion and rotation of the knee.

Anterior and posterior cruciate ligaments(PCS and ZKS) are located inside the joint capsule and cross the joint cavity.

• ACL starts from the outer edge of the tuberosity of the femur and ends at the anterior surface of the white bone, near the intercondylar eminence;
• The PCL comes from the internal condyle of the femur and is attached between the condyles of the white bone near its posterior surface.

Purpose of cruciate ligaments:

• ACL protects the knee joint from hyperextension, that is, from the forward displacement of the lower leg;
• ZKS protects against bending of the knee with posterior displacement of the lower leg.

Patella ligaments

Their purpose is free fastening of the patella.

Anterior ligament of the kneecap often referred to as the patellar ligament by our orthopedists. This is a continuation of the tendon of the quadriceps (quadriceps muscle), passing over the patella and attached to it in the upper part, and in the lower part - to the median tubercle of the white bone.

Supportive ligaments of the patella- two small ligaments (medial and lateral), which are branches of the quadriceps tendon, with which the patella is attached near the inner and outer anterior articular surface of the white bone.

Posterior ligaments of the knee

On the back of the knee are two popliteal ligaments - oblique and arcuate. Their function is to maintain the stability of the knee in its posterior sections.

oblique ligament continues the tendon of the semimembranosus muscle and begins near the medial condyle of the b / b bone. It is partially attached to the femur and is fused with the posterior surface of the articular capsule.

Arcuate ligament begins behind, simultaneously from the head of the fibula and from the external condyle of the thigh. It is attached to the posterior median surface of the white bone and then goes inward along an arc, connecting with the oblique popliteal ligament.

The tenth, smallest ligament, is located inside the joint and connects the two menisci of the knee. It is called transverse meniscus ligament.

Menisci of the knee joint

The knee joint in its structure resembles an ideal lever-hinge mechanism, in which the levers are bones, muscles and tendons, and the hinge is the joint itself with its spherical surfaces. However, the knee is an even more perfect mechanism, since it provides supports and shock absorbers.

The supporting and shock-absorbing function is performed by the menisci, external and internal. These crescent-shaped plates of collagen, which is more elastic than all other cartilage, perfectly soften the load on the joints due to their own body weight and during movement.

When the knee is bent, up to 85% of the entire load falls on the menisci. They are also able to have a stabilizing effect during injury: for example, if the ACL is torn, the lower leg will not go forward, since it will be held by the medial meniscus attached to the collateral internal ligament.

Muscles of the knee

Without muscles, our leverage would be completely helpless.

Three types of muscles are responsible for the movement of the knee:

• flexors;
• extensors;
• adductor muscles (inner side of the thigh).

Flexors

• Quadriceps: it occupies the entire front and part of the lateral surface of the thigh and consists of four heads - the femoral muscles (straight, medial wide, lateral wide, intermediate wide).
• Sartorius- one of the longest muscles of the thigh of the anterior group: it starts from the ilium (anterior upper spine), goes obliquely downward in a spiral, going to the inner front surface of the lower leg, and is attached to the tuberosity of the white bone.

Posterior extensors

Biceps- consists of two heads, starting from the ischium and femur, which at the bottom pass into the tendon, which is attached to the head of the m / b bone.

Semitendon the muscle is located closer to the medial surface, borders on the outside with the biceps, on the inside - with the semimembranosus muscle, and in the middle is closed by the gluteus maximus. It starts from the ischial tuberosity, goes around the medial condyle of the femur and is attached to the tuberosity of the white bone, forming, together with the tailor and thin muscle, a triangle called the superficial goose foot.

Semimembranosus the muscle also originates from the ischial tuberosity and, going down, branches into three bundles (one reaches the medial condyle of the white bone, the second reaches the popliteal fascia, and the third passes into the medial ligament of the knee. The membranous muscle is involved in rotational rotation of the lower leg.

Which should be well known to every person involved in sports, the largest in the human body. It is formed by three bones. The structure of the human knee joint is determined by its location. The ends of the bones that form its structure are covered with very dense cartilage tissue up to 6 mm thick. This provides one of the main functions of the articulation - shock absorption when walking.

knee joint, structure

The photo shows us the main structures of this joint: muscles, bones, menisci, ligaments (cruciate), nerves and blood vessels. Let's begin to consider its structure from the bones. The joint is formed by three bones. Two long - tubular tibial and femoral. The third is the patella. It is round and very small. Located in front. The femur below forms condyles - protrusions covered with cartilage. These protrusions are in contact with the so-called tibial plateau, which, in turn, consists of two halves. The patella moves in a groove-like depression formed by the condyles. This recess is also called patellofemoral. The fibula is located on the side of the tibia. It does not participate in the formation of the knee joint.

The structure and significance of cartilage tissue

The function of this fabric is to absorb shock loads, reducing during movements. It is needed where two bony surfaces rub against each other. Articular cartilage is very dense. At the knee joint, it covers not only the ends of the femur and tibia, but also the surface of the patella. Cartilage is of several types. In the knee joint - hyaline. A feature of this tissue is the high water content in the intercellular substance. This provides elasticity and helps protect the knee joint from injury.

The structure of ligaments and menisci

Dense connective tissue formations that fix the ends of bones are called ligaments. In the case of the knee joint, its capsule is strengthened by two such structures from the outside - medial and lateral. And two from the inside - front and rear cruciform. They limit excessive movements in the anteroposterior direction, preventing it from slipping relative to the femur. All ligaments of the knee are extremely important for its stable operation. Between the femur and tibia are two more structures called menisci. They can also be called cartilage, although their structure differs from the structure of hyaluronic that covers the articular surfaces. The menisci fill the space between the tibial plateau and the articular end of the femur.

They seem to serve as an elastic pad, redistributing weight. Without them, all his weight would be concentrated at one point on the tibial plateau. Two types of menisci (medial and lateral) are connected by a transverse ligament. Lateral (external) is less often damaged due to its greater mobility. The internal (medial) meniscus is located near the internal lateral ligament and has less lability. This is due to his frequent traumatization. In the center of the meniscus is thicker than at the edges - this forms a small depression on the tibial plateau and makes the joint more stable. If there were no ligaments, we would have a much greater imbalance in the lower limb and would more often injure the knee joint. The structure of the supporting elements of the knee provides stability to it

Synovial bags

They lie along the course of muscles and tendons. The largest is the patella (under the tendon of the quadriceps muscle), it almost does not communicate with the joint cavity. There is a deep sub-patellar bag behind, and several smaller ones in the thickness of the joint. When filling some of them with intra-articular fluid, cysts can form.

Muscles involved in joint flexion and extension

The quadriceps muscle is located on the front of the thigh. When it is reduced, the leg is extended at the knee joint. The patella lies in the thickness of the tendon, serving as a fulcrum and changing the direction of movement if necessary. It increases the strength of said muscle. The calf flexors (on the back of the thigh and near the knee) flex the leg at the knee joint.

innervation

Consider the popliteal nerve. It is the largest of those located on the back of the joint. This nerve is a branch of the sciatic nerve. It provides sensory and motor innervation to the joint capsule. Above the joint, it divides into the tibial and peroneal nerves. They are worth mentioning because they are often damaged. The obturator nerve also innervates the capsule from behind. Some branches of the tibial nerve provide sensitivity to its posterior part. The fibula innervates the posterior and anterolateral surfaces. This is due to the fact that in the body there are few such mobile formations as the knee joint - the structure and innervation with a large number of overlap zones provide high sensitivity.

blood supply

The extensive vascular network surrounding the knee consists of four large arteries that are interconnected and form the choroid plexuses (there are about 13 such networks on the surface of the joint) and inside it. The first and largest artery is the femoral. Popliteal, deep and anterior tibial are slightly smaller. All of them develop if one of the vessels is ligated. The anatomical structure can be easily represented by dividing it into three sections. The first one is the top one. Bandaging is best done at the second level. Superficial veins in the area of ​​the knee joint are located in two layers. The deeper one is represented by the great saphenous vein. Superficial - venous network from the accessory. The latter is not found in every person. The small saphenous vein arises from the posterior surface of the knee joint. Sometimes it goes with one barrel, and sometimes with two. The place of its confluence also varies, but more often flows into the popliteal.