= External anal sphincter
The <external anal sphincter> is the ring of <skeletal muscle> surrounding the distal anal canal. Its contraction helps maintain faecal continence; its <motor neurons> allow voluntary squeezing as well as reflex control. It works alongside the <smooth muscle> of the <internal anal sphincter>, so continence depends on coordinated structures rather than one isolated ring.<Anatomy and Physiology 2e by J. Gordon Betts and others>[Section 23.5, The Large Intestine, Anal Canal]{ref}
Branches of the <pudendal nerve> supply the <external anal sphincter>. Dissection of 28 cadavers found a local <nerve plexus> near the sphincters in five, illustrating why a schematic <nerve> route need not capture every individual's branching. Preserving <muscle> alone therefore does not guarantee preservation of its motor supply.<Anatomy of the pudendal nerve and its terminal branches: a cadaver study by Steven E. Schraffordt and others>[Abstract, Results: inferior rectal and perineal interconnections]{ref}
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