| Semitendinosus muscle | |
|---|---|
 Muscles of the gluteal and posterior femoral regions. Semitendinosus labeled at bottom left. | |
 Horizontal section of left thigh, viewed from above. Semitendinosus visible at bottom right. | |
| Details | |
| Origin | Lower quadrangular part of tuberosity of the ischium |
| Insertion | Pes anserinus (tibia) |
| Artery | Inferior gluteal artery, perforating arteries |
| Nerve | Sciatic (tibial, L5, S1, S2) |
| Actions | Flexion of knee, extension of the hip joint |
| Antagonist | Quadriceps muscle |
| Identifiers | |
| Latin | musculus semitendinosus |
| TA98 | A04.7.02.035 |
| TA2 | 2641 |
| FMA | 22357 |
| Anatomical terms of muscle | |
The 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 lies posteromedially in the thigh, superficial to the semimembranosus.