Which of the following does not contribute to the formation of anorectal ring in human beings?
Ans. c. Anococcygeal raphe (Ref: BDC 5/e Vot-III/p428; Maingot 11/e p 663)Anorectal ring is a muscular ring present at the anorectal junction. It is formed by the fusion of the Puborectalis, uppermost fibers of external sphincter and the internal sphincter.BDC says 'Anorectal ring is a muscular ring present at the anorectal junction. It is formed by the fusion of the Puborectalis, uppermost fibers of external sphincter and the internal sphincter. It is easily felt by a finger in anal canal. Surgical division of this ring results in rectal incontinence. The ring is less marked anteriorly where the fibers of Puborectalis are absent.'Anorectal ring is formed by fusion of:1. PuborectalisQ (a part of pubococcygeus, which in turn is a part of levator ani)2. Deep (uppermost fibers) external anal sphincterQ3. Internal anal sphincterQAnorectal RingRectal continence depends solely on the anorectal ringQ, and any damage to this ring results in rectal incontinence.The anorectal ring is muscular ring present at the anorectal junctionQ.Anorectal ring is formed by fusion ofPuborectalisQDeep external anal sphincterQInternal anal sphincterQThe Puborectalis muscle appears to be most important muscle for maintaining fecal continenceQ.
External anal sphincter
Puborectalis
Anococcygeal raphe
Internal anal sphincter
Large Intestine, Rectum, and Anal canal