The anatomy of the knee joint (R. D. Sinelnikov and other authors consider it in sufficient detail) is rather complicated. This articulation in the human body is made up of many parts. The connection takes on the most difficult loads, distributing a weight several times greater than its own. The complexity of the joint is due to its constituent parts. These are the largest bones of the lower extremities.
3 bones are involved in the formation of a joint. They are connected by a powerful articular apparatus, which includes the joint capsule, ligaments and synovial bags. The entire joint is driven by the leg muscles.
Structure of the knee joint
The knee consists of three bones, muscles that provide its movement, nerve endings and blood vessels, menisci, cruciate ligaments. Such a complex structure is due to high loads. The anatomy of the knee joint provides maximum comfort when moving on 2 limbs. Primates have a much simpler structure due to the presence of 4 limbs.
The surface of the femur (condyles) has the shape of ellipsoids. Medi althe condyle has a greater curvature than the lateral one. Between the condyles there is a patella surface. It is located in front of the femur and is divided by a vertical groove into a smaller inner and a larger outer section. They are connected to the posterior articular surfaces of the patella.
The surfaces of the condyles are slightly concave and do not correspond to the curves and curvature of the condyles of the femur. Despite this discrepancy, the interarticular cartilages (internal and external menisci) line it up.
Functions and movement
The knee joint can perform the following movements: flexion, extension and rotation. The nature of the joint is condylar. When extended, the menisci are compressed; when flexed, they are unclenched. Due to the fact that the collateral ligaments are relaxed in this position, and their attachment points are as close as possible to each other, it becomes possible to move - rotation.
When the lower leg rotates inward, the movement is limited by the cruciate ligaments, when moving outward, they relax, and the amplitude is limited to the lateral ones.
Menisci
Anatomy of the knee joint has been studying the structure and function of the menisci for many years, as injuries associated with them are very common.
Menisci are trihedral cartilaginous plates, thickened on the outside (fused to the joint capsule), inside facing the joint and pointed. From above they are concave, from below they are flattened. From the outer edges repeat the anatomy of the upper edges of the condyles of the tibia.
Lateral meniscus alongthe shape looks like part of a circle, and the medial one resembles a crescent shape.
The cartilage plates are attached anteriorly (using the transverse knee ligament) and posteriorly to the tibia (intercondylar eminence).
Main links
Brief anatomy of the knee always describes the cruciate ligaments (anterior and posterior), which are located directly in the knee. They are called intracapsular ligaments.
Besides them, there are lateral collaterals (medial and lateral) in the joint. They are also called extracapsular ligaments, as they are outside the joint capsule.
Extracapsular ligaments are represented by the tibial and peroneal collateral ligaments. They originate at the medial and lateral epicondyles of the femur and insert at the superior tibial epiphysis and lateral surface of the fibula, respectively. Both connect to the joint capsule.
Intracapsular ligaments, anterior and posterior cruciate, originate on the inner surface of the lateral and medial femoral condyle, run forward and inward (downward and inward), attach to the anterior and posterior tibial field, respectively.
Sustaining ligaments
Topographic anatomy of the knee joint, in addition to intra-articular and extra-articular, also studies other ligaments.
The ligament of the patella is called the tendon of the 4-head of the thigh muscle, which goes from top to bottom, approachespatella, wraps around it from all sides and continues down to the tibia. Lateral tendon bundles run along the sides and go from the patella to the medial and lateral condyles of the tibia. They form the external and internal supporting ligaments of the patella.
In the supporting ligaments of the patella there are also horizontal bundles that are attached to the epicondyles of the femur. The function of the supporting ligaments is to hold the patella in the desired position.
Behind the joint capsule is strengthened by an oblique popliteal ligament. It starts from the condyle of the tibia and is attached to the condyle of the femur, giving part of the bundles to the articular capsule. The ligament takes part of the bundles from the tendon of the thigh muscles, namely from the semimembranosus muscle.
The arcuate popliteal ligament is also involved in holding the patella. It starts from the femur and fibula, and is attached to the tibia. The ligament both begins and ends on the lateral condyles.
The transverse ligament of the knee connects the menisci along their anterior surface.
The anterior meniscofemoral ligament originates from the anterior portion of the medial meniscus, proceeding upward and outward to the lateral condyle of the thigh.
The posterior meniscofemoral ligament originates from the posterior edge of the outer meniscus, going up and inward to the medial femoral condyle.
The condylar knee joint works like a trochlear joint when in an extended position. The anatomy of the knee joint allows vertical rotationaxles in bent position.
Joint capsule
The joint capsule is attached to all three bones involved in the formation of the joint.
Attachment to the femur occurs under the epicondyles, to the tibia - along the articular surface, to the patella - along its articular surface.
The synovial membrane covers the joining surfaces of bones down to cartilage and lines the cruciate ligaments. In addition to the smooth structure, the membrane forms many synovial villi and folds.
The most developed folds are pterygoid. They go on the sides from the patella up. And they contain a subpatellar fat body between their sheets.
The subpatellar synovial fold lies below the bone itself, is a continuation of the pterygoid folds. It originates above the patella, goes into the joint cavity, is attached to the front edge of the fossa, between the condyles of the femur.
Synovial bags of the knee joint: anatomy and structure
The capsule of the knee joint forms several synovial bags. They can be found in various places of muscles and tendons, lying inside and between them. Bursae can be found among bones and ligaments.
The tendon of the 4th head of the thigh muscle and the anterior surface of the patella form between themselves a tendon prepatellar bag.
The patellar ligament and the tibia form a deep patellar synovial bursa. Sometimes it has a connection with the cavity of the knee joint and is separated fromit with a layer of fatty tissue.
These are the largest bursae in the knee joint.
Goose foot of the knee joint: anatomy and location
For normal operation of the knee joint, there are a number of muscles that can be divided according to their location:
- Anterior thigh - quadriceps.
- Back of the thigh - biceps, semitendinosus, semimembranosus.
- Inner thigh - large, thin, long, short, adductor, pectus muscle.
On the lower leg there is a place where 3 thigh muscles are attached - tailor, semitendinosus and thin. In this place, the crow's foot is formed, where the synovial bag is located.
Knee injuries
Knee injury is very common. In order to diagnose the cause of joint pain, the doctor very often prescribes an MRI. The anatomy of the knee joint (bones, ligaments, muscles, arteries, etc.) is visible on the picture, which will determine the cause of discomfort.
Very often athletes get knee injuries, as well as those whose work is associated with physical labor. In order to reduce the risk of injury to the knee joint, it is necessary to regularly strengthen the muscles and ligaments. Perform simple exercises from articular gymnastics, regularly drink vitamin and mineral complexes. All these measures help strengthen the knee joint and the muscles that move it.
