Overview
It lies medial to the semitendinosus and divides into two bellies, one to the femur and one to the tibia. In the carcass it is the topside (inside round).
Origin
Ischiatic tuberosity (tuber ischiadicum), on its ventral surface.
Insertion
- Cranial belly: medial epicondyle of the femur.
- Caudal belly: medial condyle of the tibia.
Action
Extends the hip and adducts the limb; depending on the position of the stifle it helps extend or flex it.
Innervation
Sciatic nerve (n. ischiadicus).
Clinical relevance
In nutritional myodegeneration (white muscle disease) of calves, caused by selenium and vitamin E deficiency, the large muscles of the pelvic limbs, such as this one, show pale streaks of necrosis, often symmetrical on both sides. The calf is stiff, weak or unable to rise.