Transverse perineal muscle
The transverse perineal muscles are important for the stability of the pelvic and perineal structures via their intimate relationship with the perineal body. For many years, it was thought that these muscles directly inserted into the perineal body. It is now known that fibers from the muscles on each side split to pass around and envelope the perineal body and cross the midline merging with the contralateral muscle.
The transverse perineal muscles are separated by the perineal membrane: