| Sphincter urethrae membranaceae muscle | |
|---|---|
| The male urethra laid open on its anterior (upper) surface. (Region visible, but muscle not labeled.) | |
| Coronal section of anterior part of pelvis, through the pubic arch. Seen from in front. (Region visible, but muscle not labeled.) | |
| Latin | musculus sphincter urethrae externus urethrae masculinae, musculus sphincter urethrae membranaceae |
| Gray's | subject #120 429 |
| Origin | Junction of the inferior rami of the pubis and ischium to the extent of 1.25 to 2 cm. |
| Insertion | Ischiopubic rami |
| Artery | |
| Nerve | Branches from Dorsal nerve of the penis |
| Actions | Constricts urethra, maintain urinary continence |
The external sphincter muscle of urethra (or sphincter urethrae membranaceae) surrounds the whole length of the membranous portion of the urethra, and is enclosed in the fasciæ of the urogenital diaphragm.
Its external fibers arise from the junction of the inferior rami of the pubis and ischium to the extent of 1.25 to 2 cm., and from the neighboring fasciæ.
They arch across the front of the urethra and bulbourethral glands, pass around the urethra, and behind it unite with the muscle of the opposite side, by means of a tendinous raphé.
Its innermost fibers form a continuous circular investment for the membranous 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 As such, some of the information contained within it may be outdated.
|
||||||||||||||||||||||||||||||||||||||||