Buttocks
The paired rounded areas of the body’s posterior, formed mainly by the gluteal muscles and overlying tissue.
Gluteus maximus: The largest gluteal muscle, extending the hip and helping stabilize the trunk and leg. It supplies most of the buttocks’ muscular bulk and powers hip extension.
Hip extension: Movement that increases the angle between the thigh and the front of the trunk. The gluteus maximus drives this movement when standing up, climbing, or running.
Intramuscular injection: Delivery of medication into muscle through a needle. The gluteal region is a possible injection site, but placement must avoid nerves and blood vessels.
Hip: The joint and surrounding region where the thigh meets the pelvis. The hip is lateral to the buttocks, though both regions contribute to lower-body movement.
Gluteus medius: A muscle on the outer pelvis that abducts the hip and stabilizes the pelvis during walking. It lies beneath the upper outer buttock and supports pelvic balance.
Hip abduction: Movement of the thigh away from the body's midline. The gluteus medius and minimus abduct the hip and steady the pelvis.
Gluteal tendinopathy: Painful tendon disease involving the gluteus medius or minimus, commonly near the greater trochanter. It causes pain at the outer hip, near the upper lateral buttock.
Thigh: The portion of the lower limb between the hip and the knee. The thigh lies below the buttocks and is anatomically distinct despite their adjoining contours.
Gluteus minimus: The deepest and smallest of the three gluteal muscles, aiding hip abduction and rotation. Its position beneath gluteus medius helps form the deep muscular layer.
Superior gluteal nerve: A nerve arising from the sacral plexus that supplies gluteus medius, gluteus minimus, and tensor fasciae latae. Damage can weaken pelvic stabilization and produce a waddling gait.