sphincter muscle of urethra

n.
  1. A muscle with origin from the ramus of the pubis, with insertion with its fellow muscle in the median raphe behind and in front of the urethra, with nerve supply from the pudendal nerve, and whose action constricts the membranous urethra.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.