Gluteal sulcus
The gluteal sulcus (also known as the gluteal fold, tuck, fold of the buttock, or horizontal gluteal crease) is an area of the body of humans and anthropoid apes, described by a horizontal crease formed by the inferior aspect of the buttocks and the posterior upper thigh. The gluteal sulcus is formed by the posterior horizontal skin crease of the hip joint and overlying fat and is not formed by the lower border of the gluteus maximus muscle, which crosses the fold obliquely. It is one of the major defining features of the buttocks. Children with developmental dysplasia of the hips are born with uneven gluteal folds and can be diagnosed with a physical examination and sonogram. Gluteal muscles The gluteal muscles can be classified into two main groups: The superficial gluteal muscles are responsible for extension and abduction of the hip as well as stabilizing and maintaining the balance of the pelvis during the gait cycle. Deep gluteal muscles control external rotation of the extended hip and abduction of the flexed hip. Clinical relevance The superolateral region, which is free of nerves and vessels, is used for intramuscular injections. The Trendelenburg gait, consisting of gluteus medius and minimus muscles,