Semimembranosus

The semimembranosusExtensor / Flexor Deep to semitendinosus; extends hip and flexes knee on the inner thigh muscle is a large, flat muscle located at the back of the thigh. 

Origin

The semimembranosus muscle originates from the ischial tuberosityRough, thick projection that bears body weight when sitting; major hamstring attachment., a bony prominence located at the baseA substance that accepts hydrogen ions (H⁺) or releases hydroxide ions (OH⁻). of the pelvis. Specifically, it arises from the superiorAbove or toward the upper part of the body. part of the tuberosity.

Insertion

The semimembranosus muscle inserts into the medial condyleInner rounded bump at distal end; articulates with tibia and meniscus. of the tibiaShinbone; large, weight-bearing medial bone of the lower leg., a large bone in the lower leg. It attaches to the posterior part of the medialToward the midline of the body condyle. This attachment aids in the flexion of the knee. It also stabilizes the knee joint.

Actions

Knee Flexion

Thigh Extension

Medial Rotation of the Tibia

Interactive Materials