Final answer:
The region between the butt cheeks near the tailbone is called the perineum. It is a diamond-shaped space located just inferior to the pelvic diaphragm, between the pubic symphysis, coccyx, and ischial tuberosities.
Step-by-step explanation:
The region between the butt cheeks near the tailbone is called the perineum. It is a diamond-shaped space located just inferior to the pelvic diaphragm, between the pubic symphysis, coccyx, and ischial tuberosities. In females, the perineum also contains the compressor urethrae and the sphincter urethrovaginalis, while in males, there is the deep transverse perineal muscle.