Semimembranosus muscle

Semimembranosus muscle is one of the three hamstring muscles that are located at the back of the thigh. The other two are the semitendinosus muscle and the biceps femoris muscle. The semimembranosus muscle is the most medial of the three hamstring muscles.

Anatomy

The semimembranosus muscle originates from the ischial tuberosity, the sit bone. It extends down the back of the thigh to the medial side of the knee. It inserts on the posterior part of the medial tibia.

The semimembranosus muscle is named for its flat tendon of origin. It is broader above than below, its medial margin is thicker and rounder than the lateral.

Function

The semimembranosus muscle has several functions. It helps to extend the hip joint and flex the knee joint. It also helps to medially rotate the knee: the tibia medially rotates on the femur when the knee is flexed and medially rotates the femur when the hip is extended. It counteracts forward bending at the hips.

Clinical significance

Injury to the semimembranosus muscle is a common sports injury, particularly in sports that involve running and jumping. It can also be injured in falls and other types of accidents. Treatment usually involves rest, ice, compression, and elevation (RICE). In severe cases, surgery may be required.

See also

• Hamstring
• Semitendinosus muscle
• Biceps femoris muscle

Semimembranosus muscle

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  Semimembranosus muscle
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  Gray's Anatomy illustration of the semimembranosus muscle
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  Gray's Anatomy illustration of the muscles of the thigh
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  Gray's Anatomy illustration of the posterior view of the thigh
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  Gray's Anatomy illustration of the muscles of the leg
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  Gray's Anatomy illustration of the lower limb
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  Femoral biceps muscle
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  Histological slide of muscle tissue
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  Histological slide of muscle tissue
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  Histological slide of muscle tissue
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  Histological slide of muscle tissue