filling internal urethral orifice

filling internal urethral orifice

[TA]
the internal urethral orifice after the bladder begins to be distended by urine, when the trigonal muscles are contracted and the detrusor muscle is relaxed; during this stage the orifice occurs at a higher level and is bounded by a different portion of the mucosa than during voiding.
See also: voiding internal urethral orifice.