Anatomy of the Semitendinosus Muscle

Courtesy: Prof Nabil Ebraheim, University of Toledo, Ohio, USA

Semitendinosus is one of the three muscles that make up the hamstrings muscle group, and it is located at the posterior and medial aspect of the thigh
The hamstring muscles are- semitendinosus, semimembranosus and biceps femoris. It is a cylinder muscle- starts and ends as tendon and it looks like a membrane

Origin
Upper medial part of ischial tuberosity by a tendon, common to the long head of biceps femoris and semitendinosus

Insertion
Upper part of medial surface of tibia, called the Pes Anserine area along with gracilis and sartorius( called as the Pes Anserine tendons)

Nerve supply
Tibial part of sciatic nerve

Actions
1.Flexion of knee
2Extension of hip (weak function)
3.Medial rotation of knee