External sphincter muscle of male urethra

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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
Action:	Constricts urethra, maintain urinary continence
Dorlands /Elsevier	m_22/13540449

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.

[edit] Additional images

Right hip bone. Internal surface.

[edit] External links

• LUC sphu
• sphincter+urethrae at eMedicine Dictionary
• SUNY Figs 41:06-04 - "Muscles of the female urogenital diaphragm (deep perineal pouch) and structures located inferior to it."

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

v • d • e List of muscles of torso BACK splenius (capitis, cervicis) - erector spinae (iliocostalis, longissimus, spinalis) - latissimus dorsi transversospinales: (semispinalis dorsi, semispinalis cervicis, semispinalis capitis, multifidus, rotatores) - interspinales - intertransversarii SUBOCCIPITAL rectus capitis posterior (major, minor) - obliquus capitis (inferior, superior) CHEST intercostales (external, internal, innermost) - subcostales - transversus thoracis - levatores costarum - serratus posterior (inferior, superior) - diaphragm ABDOMEN anterior/lateral wall: obliques (external, internal) - transversus abdominis - rectus abdominis - pyramidalis posterior wall: quadratus lumborum - psoas major/psoas minor - iliacus cremaster PELVIS/FLOOR levator ani (iliococcygeus, pubococcygeus, puborectalis) - coccygeus PERINEUM anal triangle: sphincter ani (externus, internus) superficial perineal pouch (superficial transverse perineal, bulbospongiosus, ischiocavernosus) deep perineal pouch (deep transverse perineal, sphincter urethrae membranaceae)

v • d • e Anatomy: urinary system Abdomen Kidneys • Ureters • Orifice of ureter Pelvis Urinary bladder (Uvula, Trigone, Detrusor, Apex, Neck) Urethral sphincters (External sphincter muscle of male urethra, External sphincter muscle of female urethra, Internal sphincter muscle of urethra) Urethra Development Development of the urinary and reproductive organs