Labels:daily OCR: SEMITEND INOSUS OUR SEMITENDINOSUS muscles are found in the hamstrings at the back ot your legs. Like the biceps femoris and semimem branosus muscles, these two muscles straighten the legs 1 the hips, and bend them at knee They are attacl hed to the back of the pelvis, or hip and to one of the two lower leg bones vour nbranosus attached