per·i·ne·um 
(pĕr′ə-nēəm)
(pĕr′ə-nēəm)n. pl. per·i·ne·a (-nēə)
1. The portion of the body in the pelvis occupied by urogenital passages and the rectum, bounded in front by the pubic arch, in the back by the coccyx, and laterally by part of the hipbone.
2. The region between the scrotum and the anus in males, and between the posterior vulva junction and the anus in females.
[Middle English, from Medieval Latin perinaeon, from Greek perinaion : peri-, peri- + inān, to excrete.]
per′i·neal (-nēəl) adj.