Search results
Results from the WOW.Com Content Network
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]
Defects of the external anal sphincter are associated with urge incontinence. [22] The external anal sphincter is supplied by the pudendal nerve. Damage to the nerve supply of the external anal sphincter on one side may not result in severe symptoms because there is substantial overlap in innervation by the nerves on the other side. [2]
Generally, fissures are due to injury to the mucosa, or because of a poor local blood supply that prevents proper healing, with spasm of the external anal sphincter contributing. [9] The external anal sphincter can be relaxed by the application of glyceryl trinitrate creams, and constipation is managed with laxatives and improving hydration. [9]
Anal encirclement effectively supplements the anal sphincter, narrowing the anal canal and its barrier function to stool, without altering voluntary control. Since complications are common, and can be serious (fecal impaction, infection, erosion of encirclement through anal canal), modern surgeons prefer to perform colostomy.
The external anal sphincter muscle is the voluntary muscle that surrounds and adheres to the anus at the lower margin of the anal canal. This muscle is in a state of tonic contraction, but during defecation, it relaxes to allow the release of feces. Movement of the feces is also controlled by the involuntarily controlled internal anal sphincter ...
The anal wink, anal reflex, perineal reflex, or anocutaneous reflex is the reflexive contraction of the external anal sphincter upon stroking of the skin around the anus. [ 1 ] A noxious or tactile stimulus will cause a wink contraction of the anal sphincter muscles and also flexion.
The function of the muscle is fixation of the perineal body (central tendon of perineum), support of the pelvic floor, expulsion of semen in males and last drops of urine in both sexes. [2] The deep transverse perineal muscle lies in the same plane as the urethral sphincter and formerly the two muscles were described together as the constrictor ...
The rectococcygeal muscles are composed of smooth muscle and run from the anterior surface of the 2nd and 3rd coccygeal vertebrae down the posterior wall of the rectum as a triangular shaped muscle before branching and inserting among the various muscles and fascial structures associated with the pelvic diaphragm and anal canal and collectively called longitudinal anal muscles.