Origin
Ischiatic tuberosity (tuber ischiadicum).
Insertion
Medial surface of the proximal tibia and, by a tarsal tendon joining the common calcanean tendon, the calcaneal tuber.
Action
Extends the hip, flexes the stifle and extends the tarsus.
Innervation
Sciatic nerve (n. ischiadicus).
Clinical relevance
Fibrotic myopathy of the semitendinosus, described mainly in German Shepherd dogs, shortens the stride of the pelvic limb, with a quick medial flick of the paw at the end of the swing phase.