Search results
Results from the WOW.Com Content Network
The internal anal sphincter, 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 5 mm thick, and is formed by an aggregation of the smooth (involuntary) circular muscle fibers of the rectum.
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]
The anal canal is the part that connects the rectum to the anus, located below the level of the pelvic diaphragm. [1] It is located within the anal triangle of the perineum, between the right and left ischioanal fossa. As the final functional segment of the bowel, it functions to regulate release of excrement by two muscular sphincter complexes ...
The inferior rectal nerves (inferior anal nerves, inferior hemorrhoidal nerve) usually branch from the pudendal nerve but occasionally arises directly from the sacral plexus; they cross the ischiorectal fossa along with the inferior rectal artery and veins, toward the anal canal and the lower end of the rectum, and is distributed to the sphincter ani externus (external anal sphincter, EAS) and ...
The conjoint longitudinal muscle is a muscle layer in the wall of the anal canal between the internal anal sphincter (deep to CLM) and external anal sphincter (superficial to CLM). It is continuous proximally with the longitudinal (outer) smooth muscle layer of the rectum. It receives autonomic innervation in common with the internal anal ...
The deep branch of the perineal nerve (or muscular branches) is a nerve of the perineum. It is a branch of the perineal nerve , from the pudendal nerve . It supplies the superficial transverse perineal muscle , bulbospongiosus muscle , ischiocavernosus muscle , the bulb of penis , levator ani , and the external anal sphincter .
The anococcygeal body (anococcygeal ligament or anococcygeal raphe) is a fibrous median raphe in the floor of the pelvis, which extends between the coccyx and the margin of the anus.
In mammals, invertebrates and most fish, [1] [2] the anus (pl.: anuses or ani; from Latin, 'ring' or 'circle') is the external body orifice at the exit end of the digestive tract (), i.e. the opposite end from the mouth.