Coronal section through the anal canal. B. Cavity of urinary bladder V.D. Ductus deferens. S.V. Seminal vesicle. R. Second part of rectum. A.C. Anal canal. L.A. Levator ani. I.S. Sphincter ani internus. E.S. Sphincter ani externus.
Details
Nerve
Branch from the fourth sacral and contributions from the inferior hemorrhoidal branch of the pudendal nerve
Actions
Keep the anal canal and orifice closed
Identifiers
Latin
sphincter ani externus
TA98
A04.5.04.012
TA2
2426
FMA
21930
Anatomical terms of muscle
[edit on Wikidata]
The external anal sphincter (or sphincter ani externus) is an oval tube of skeletal muscle fibers.[1] Distally, it is adherent to the skin surrounding the margin of the anus.[2] It exhibits a resting state of tonical contraction[1] and also contracts during the bulbospongiosus reflex.[3][4][5][6]
^ abStandring, Susan (1201). Gray's Anatomy: The Anatomical Basis of Clinical Practice (42th ed.). New York. p. 683. ISBN 978-0-7020-7707-4. OCLC 1201341621.
^Gray, Henry (1918). Gray's Anatomy (20th ed.). pp. 424–425.
^Vodušek DB, Deletis V (2002). "Intraoperative Neurophysiological Monitoring of the Sacral Nervous System". Neurophysiology in Neurosurgery, A Modern Intraoperative Approach: 153–165. doi:10.1016/B978-012209036-3/50011-1. ISBN 9780122090363. S2CID 78605592.
^Sarica Y, Karacan I (July 1987). "Bulbocavernosus reflex to somatic and visceral nerve stimulation in normal subjects and in diabetics with erectile impotence". The Journal of Urology. 138 (1): 55–58. doi:10.1016/S0022-5347(17)42987-9. PMID 3599220.
^Jiang XZ, Zhou CK, Guo LH, Chen J, Wang HQ, Zhang DQ, et al. (December 2009). "[Role of bulbocavernosus reflex to stimulation of prostatic urethra in pathologic mechanism of primary premature ejaculation]". Zhonghua Yi Xue Za Zhi (in Chinese). 89 (46): 3249–3252. PMID 20193361.
^Podnar S (February 2012). "Clinical elicitation of the penilo-cavernosus reflex in circumcised men". BJU International. 109 (4): 582–585. doi:10.1111/j.1464-410X.2011.10364.x. PMID 21883821. S2CID 27143105.
and 29 Related for: External anal sphincter information
The externalanalsphincter (or sphincter ani externus) is an oval tube of skeletal muscle fibers. Distally, it is adherent to the skin surrounding the...
The internal analsphincter, IAS, or sphincter ani internus is a ring of smooth muscle that surrounds about 2.5–4.0 cm of the anal canal. It is about...
primary function of the anus. These are the internal analsphincter and the externalanalsphincter, which are circular muscles that normally maintain constriction...
internal analsphincter and externalanalsphincter. The inner sphincter is involuntary and the outer is voluntary. The microscopic precapillary sphincters function...
white line between the mucous membrane and internal analsphincter muscle. The externalanalsphincter muscle is the voluntary muscle that surrounds and...
The anal glands or anal sacs are small glands near the anus in many mammals. They are situated in between the externalanalsphincter muscle and internal...
The anal wink, anal reflex, perineal reflex, or anocutaneous reflex is the reflexive contraction of the externalanalsphincter upon stroking of the skin...
the internal analsphincter contributes more to the resting tone of the anal canal than the externalanalsphincter. The internal sphincter is responsible...
of the anus (corrugator cutis ani, the internal anal sphincter and the externalanalsphincter) The medial muscles of the urogenital region (the superficial...
desire to pass feces, a process called defecation. An internal and externalanalsphincter, and resting contraction of the puborectalis, prevent leakage of...
Externalsphincter muscle may refer to: ExternalanalsphincterExternalsphincter muscle of female urethra Externalsphincter muscle of male urethra This...
veins, toward the anal canal and the lower end of the rectum, and is distributed to the sphincter ani externus (externalanalsphincter, EAS) and to the...
removing the internal and externalanalsphincter, with concomitant fecal incontinence. For this reason, many patients with anal cancer have required permanent...
nerve stimulation. Functional deficits of the externalanalsphincter (EAS) and/or internal analsphincter (IAS), i.e. where there is no structural defect...
involuntary relaxation of the internal analsphincter in response to distention of the rectum. The RAIR provides the upper anal canal with the ability to discriminate...
with normal anal canal pressure, focal defects such as the keyhole deformity can be the cause of substantial symptoms. Externalanalsphincter (EAS) dysfunction...
atrophy of the externalanalsphincter. Some authors suggest that pudendal nerve damage is the cause for pelvic floor and analsphincter weakening, and...
A rectal or anal dilator is a medical device similar to a speculum designed to open and relax the internal/externalanalsphincter and rectum in order...
pelvic muscles, including the male or female external urethral sphincter and the externalanalsphincter. If damaged, most commonly by childbirth, loss...
the muscle of the opposite side, joining with the fibers of the externalanalsphincter and transverse perineal muscles, at the central tendinous point...
known respectively as the upper esophageal sphincter and the lower esophageal sphincter. These sphincters act to close the esophagus when food is not...
relaxation of the internal analsphincter, and an initial contraction of the skeletal muscle of the externalanalsphincter. If the urge is not acted upon...
partner during anal or vaginal sex as an attempt by the penetrating partner to induce involuntary tightening of internal or externalanalsphincter muscles or...
the duodenum. The orifice is surrounded by a sphincter, a band of muscle, called the pyloric sphincter. The word pylorus comes from Greek πυλωρός, via...
bulbospongiosus muscle, superficial transverse perineal muscle, and externalanalsphincter muscle converge to form this major supportive structure of vagina...
outwards along the 5 or 7 o'clock position to avoid the internal and externalanalsphincter. This procedure is also not widely practised. Traditionally, physicians...
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