Biceps femoris - hybrid muscle - have two nerves supply - Present in posterior compament (lateral) of thigh It has two heads Long head: 1. Originates from inferomedial pa of upper area of ischial tuberosity. 2. Innervated by sciatic nerve - common fibular division. Sho head: 1. Arise from lateral lip of Linea aspera on shaft of femur. 2. innervated by sciatic nerve - common fibular division. It flexes & laterally rotates leg at knee joint; Extends & laterally rotates thigh at hip joint Long head is a pa of hamstrings while sho head is not - gracilis, adductor longus, adductor magnus - belong to medial compament of thigh Muscle Origin Inseion Innervation Function * Gracilis A line on external surface of body of pubis, the inferior pubic ramus & ramus of ischium Medial surface of proximal shaft of tibia. Obturator nerve (L2, L3) Adducts thigh at hip joint & flexes leg at knee joint. * Adductor longus External surface of body of pubis (triangular depression inferior to pubic crest & lateral to pubic symphysis) Linea aspera on middle 1/3rd of shaft of femur Obturator nerve (anterior division L2, L3, L4) Adducts & medially rotates thigh at hip joint * Adductor magnus Ischiopubic ramus Ischial tuberosity Adductor pa - Posterior surface of proximal femur, Linea aspera, medial supracondylar line Hamstring pa - Adductor tubercle, medial supracondylar line Obturator N (L2, L3, L4) Sciatic N (tibial division) (L2, L3, L4) Adducts & medially rotates thigh at hip joint Extends thigh at hip joint.