It arises by a thin aponeurosis from the anterior margins of the lower half of the symphysis pubis and the upper half of the pubic arch.
The muscle's fibers run vertically downward, ending in a rounded tendon. This tendon passes behind the medial condyle of the femur, curves around the medial condyle of the tibia where it becomes flattened, and inserts into the upper part of the medial surface of the body of the tibia, below the condyle. For this reason, the muscle is a lower limb adductor. At its insertion the tendon is situated immediately above that of the semitendinosus muscle, and its upper edge is overlapped by the tendon of the sartorius muscle, which it joins to form the pes anserinus. The pes anserinus is separated from the medial collateral ligament of the knee-joint by a bursa.
A few of the fibers of the lower part of the tendon are prolonged into the deep fascia of the leg.
By its inner or superficial surface gracilis is in relation with the fascia lata, and below with the sartorius and internal saphenous nerve; the internal saphenous vein crosses it lying superficially to the fascia lata.
By its outer or deep surface with the adductor longus, brevis, and magnus, and the internal lateral ligament of the knee-joint, from which it is separated by a synovial bursa common to the tendons of the gracilis and semitendinosus.