Gluteal cleft

The gluteal cleft, natal cleft or anal cleft is the groove or crack between the buttocks that runs from just below the sacrum to the perineum, so named because it forms the visible border between the external rounded protrusions of the gluteus maximus muscle. The gluteal cleft is above the location of the anus.

A number of slang terms exist for the gluteal cleft, such as buttcrack.