Internal urethral orifice
Urinary bladder
The interior of bladder.
Latin	ostium urethrae internum
Gray's	subject #255 1232

The internal urethral orifice is the opening of the urinary bladder into the urethra. It is placed at the apex of the trigonum vesicae, in the most dependent part of the bladder, and is usually somewhat crescent-shaped; the mucous membrane immediately behind it presents a slight elevation in males, the uvula vesicae, caused by the middle lobe of the prostate.

[edit] See also

• Internal sphincter muscle of urethra

[edit] External links

• Internal+urethral+orifice at eMedicine Dictionary
• SUNY Labs 44:06-0106 - "The Male Pelvis: The Urethra"

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.

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