urogenital hiatus

The free anterior border of the levator ani are separated by a gap(hiatus) through which the urethra (& in the female, the vagina) passes. The external urethral sphincter & deep transverse perineal muscles also lie within this gap.

References

Clinically Oriented Anatomy, 4th edition, KL Moore & AF Dalley (eds), Lippincott Williams & Wilkins, Philadelphia, PA 1999.