Semitendinosus

Semitendinosus (/ˌsɛmiˌtɛndɪˈnoʊsəs/) is a long superficial muscle in the back of the thigh. It is so named because it has a very long tendon of insertion. It belongs to the hamstring group.

Etymology

The term "Semitendinosus" is derived from the Latin words "semi," meaning half, and "tendinosus," meaning pertaining to a tendon. This is due to the muscle's long tendinous nature.

Anatomy

The Semitendinosus muscle originates from the ischial tuberosity, the lower and back part of the hip bone. It runs down the back of the thigh and inserts into the upper part of the tibia, one of the bones in the lower leg. It works in conjunction with the other hamstring muscles to flex the knee and extend the hip.

Function

The primary functions of the Semitendinosus muscle are to flex the knee and extend the hip. It also helps in the inward rotation of the knee. When the knee is flexed, semitendinosus internally rotates the knee. It is also used to counteract the forward bending at the hips.

Related Terms

Hamstring: A group of three muscles in the back of the thigh that affect hip and knee movement.
Ischial tuberosity: The sit bone, a large swelling posteriorly on the superior ramus of the ischium.
Tibia: The shinbone or shankbone, the larger and stronger of the two bones in the leg below the knee.