(Netter Basic Science) Frank H. Netter - Atlas of Human Anatomy-Elsevier (2018)

Anorectal Musculature
See also Plate 381
Rectosigmoid
junction
Anterior view
Sigmoid colon
Free taenia
Fibers of taenia spread out to form longitudinal muscle layer of rectum
Fibers from longitudinal muscle join circular muscle layer
Window cut in longitudinal muscle layer to expose underlying
Circular muscle layer
Levator ani muscle
Coronal section
Deep
Superficial
Subcutaneous
Parts* of
external anal
sphincter muscle
Fibrous septum
Corrugator cutis
ani muscle
Perianal skin
Superior fascia of pelvic diaphragm
Inferior fascia of pelvic diaphragm
Levator ani muscle
Rectal fascia
Longitudinal muscle of rectum
Circular muscle of rectum
Muscularis mucosae of rectum
Deep part* of external anal sphincter muscle
Internal rectal venous plexus
Conjoined longitudinal muscle
Superficial part* of external anal sphincter muscle
Internal anal sphincter muscle
Muscularis mucosae of anal canal
Transverse fibrous septum of ischioanal fossa
Subcutaneous part* of external anal sphincter muscle
Corrugator cutis ani muscle
*Parts variable and often indistinct
External rectal venous plexus
Intersphincteric
groove
(anocutaneous
line)
Plate 376
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Rectum