The hip is one of the most flexible joints in the entire human body. The many muscles of the hip provide movement, strength, and stability to the hip joint and the bones of the hip and thigh. These muscles can be grouped based upon their location and function. The four groups are the anterior group, the posterior group, adductor group, and the abductor group.
The anterior muscle group features muscles that flex (bend) the thigh at the hip. These muscles include the iliopsoas group (which consists of the psoas major and iliacus muscles) and the quadriceps femoris group (which consists of the rectus femoris, vastus intermedius, vastus lateralis, and vastus medialis).
The posterior muscle group is made up of the muscles that extend (straighten) the thigh at the hip. These muscles include the gluteus maximus muscle (the largest muscle in the body) and the hamstrings group (which consists of the biceps femoris, semimembranosus, and semitendinosus muscles). Climbing stairs, standing, walking, and running are all activities that require strong contractions from the posterior muscle group to extend the leg.
The adductor muscle group, also known as the groin muscles, is a group located on the medial side of the thigh. These muscles move the thigh toward the body’s midline. Included in this group are the adductor longus, adductor brevis, adductor magnus, pectineus, and gracilis muscles. Overstretching of these muscles caused by rapid lateral movement the thigh can lead to a groin pull, a common sports injury.
The abductor muscle group is located on the lateral side of the thigh and moves the thigh away from the body’s midline. These muscles include the piriformis, superior gemellus, inferior gemellus, tensor fasciae latae, sartorius, gluteus medius, and gluteus minimus muscles. Spreading the legs to do a split is an example of a movement involving the abductor muscles.