Semimembranosus muscle
Muscles · Latin: Musculus semimembranosus
The semimembranosus muscle is the most medial of the three hamstring muscles in the thigh.
It is so named because it has a flat tendon of origin.
It lies posteromedially in the thigh, deep to the semitendinosus muscle.
It extends the hip joint and flexes the knee joint.
Definition from Wikipedia, CC BY-SA 4.0.