Semimembrane thigh muscle: location, structure, pathology

The hip muscles surrounding the femur, depending on the location, are divided into several groups: anterior, posterior and medial. The rear group is responsible for straightening and straightening the body, extension of the hips in the hip joints and flexion of the shins in the knee joints.

The rear group consists of the following muscles:

• biceps;

• Semitendinosus and semimembranous muscles.

Location:

The semimembranous femur muscle is located under the semitendinous muscle. Muskulus semimembranosus (semimembranous muscle) begins from the lamellar tendon, which forms the entire upper part of it, attaching to its upper part to the sciatic tubercle, and then descends along the medial (internal) edge of the thigh. The final (distal) tendon of the semimembranous muscle disintegrates in the area of the lower anchorage into three tendon pencils that form deep crow's feet on each of the thighs.

One of the bundles is attached to the fascia, which covers the popliteal muscle, the second - to the inner condyles of the tibia bones on both legs, the third, wrapped around the back wall of the knee, is part of the posterior oblique knee ligament.

Where the tendon of the muscle is divided into several bundles, a synovial bag (bursa muskulus semimembranosi) of the semimembranous muscle is located.

Functions

Semimembranous muscle performs a number of important functions, ensuring the movement of the lower extremity in the hip and knee joints:

• Flexes the tibia in the knee joints.
• Rotation (rotation) of the shins inside with bent knees (the muscle protects the synovial membrane from pinching by pulling the capsule of the knee joints).
• Thigh extension in the hip joints.
• Tonic muscle.
• If the tibia is fixed, the semimembranous muscles along with the large gluteal muscles are responsible for extension of the trunk.

Nutrition and innervation

The sememembranous muscle is blood flowed with an artery that wraps the femur, popliteal and perforating arteries.

The innervation of the muscle is performed by the tibial nerve.

Diseases of the semimembranous muscle

1. Injuries - stretching of three degrees of severity, including a partial and complete rupture.

2. Tendopathy is a pathology that manifests itself in painful sensations in the posterior internal parts of the knee joint, which increase after rising on inclined surfaces, prolonged running, and also bending knee joints with resistance. In this case, the maximum soreness is determined in the places of attachment of tendons on the posterior medial surface of the tibia slightly below the joint boundary. Between the capsule of the knee joint, the medial part of the gastrocnemius muscle and the tendon there is a bag inside which chronic bursitis can develop. It is necessary to conduct differential diagnosis with intra-articular pathology. Tendopathy of the semimembranous muscle is treated similarly to the tendonopathies of other localizations.

3. An incision in the goose paw region is manifested with increased external rotation or when trying to turn the knee inwards with a fixed shin (gymnastics, football, skiing). Clinical manifestations: increasing local swelling, painful sensations during palpation, which are amplified when trying to remove the shin from its forced position of internal rotation. The most common damage to the goose-foot is combined with damage to other stabilizing structures of the knee joint. Differential diagnosis of this pathology should be carried out with injuries of the inner meniscus (its horn) and bursitis in this area.

4. Cysts of the popliteal fossa (Becker cyst) is an inflammatory process in the area of the mucous membrane of the semimembranous and gastrocnemius muscle (the presence of such bags occurs in 60% of healthy people and is not a deviation from the norm). Clinically, the cyst manifests itself in the form of a dense-elastic tumor in the upper part of the popliteal fossa, edema, an increase in size (due to which the surrounding structures are compressed), discomfort, pain and movement restriction. More often the cyst arises again as a consequence of the overgrowth of the bag with liquid in case of chronic inflammation of the knee joint, which has a different etiology (rheumatism, tuberculosis, various traumas, osteoarthritis and others).