Anal sphincter
Updates to Article Attributes
Body
was changed:
Anal sphincters can be categorised by internal and external anal sphincters
Gross anatomy
Internal anal sphincter
- continuation of inner rectal muscle
- thickened, circular muscle fibres, up to 5mm thick
- composed of visceral muscle
External anal sphincter
- composed of skeletal muscle
- classically categorised into deep, superficial
(middle), and subcutaneous parts
Deep part
- circular muscle fibres
- blends with puborectalis part of levator ani (posteriorly and laterally)
- the aforementioned region is called the anorectal ring, and is palpable on rectal examination
Superficial part
- elliptical muscle fibres
- attaches from the the tip of the coccyx posteriorly to the perineal body anteriorly
- only part of the sphincter with bony attachment
Subcutaneous part
- circular muscle fibres
- lower ends curve inwards, lying below the end of the internal sphincter, the intersphincteric groove that results is palpable on examination
-<li>classically categorised into deep, superficial (middle), and subcutaneous parts</li>- +<li>classically categorised into deep, superficial, and subcutaneous parts</li>
References changed:
- 1. McMINN. Lasts Anatomy Regional and Applied. CHURCHILL LIVINGSTONE. (2003) ISBN:B0084AQDG8. <a href="http://books.google.com/books?vid=ISBNB0084AQDG8">Read it at Google Books</a> - <a href="http://www.amazon.com/gp/product/B0084AQDG8">Find it at Amazon</a><span class="ref_v3"></span>
Sections changed:
- Anatomy
Systems changed:
- Musculoskeletal
- Gastrointestinal
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