On The Etiology of the Electric Activity of the External Anal and Urethral Sphincters

Abstract

Histologic examination revealed the presence of smooth muscle fibers, between the skeletal fibers of the external anal and urethral sphincters. Evidence suggests that the smooth muscle fibers are the source of the electric activity of the sphincters and might explain some physiologic phenomena such as the external anal contraction on rectal distension or on coughing.

Pudendal Neuropathy Alone Results in Urge Incontinence Rather Than in Complete Fecal Incontinence

“…the probability of the pudendal nerve being responsible for unconscious contraction, however, is not supported by the multiple regression analysis showing that unconscious contraction is not predicted by anal electrosensitivity, representing the pudendal nerve. furthermore, this probability is also not supported by the recent findings of shafik et al 16 on the innervation of the external anal sphincter. they demonstrated the presence of smooth muscle fibers in the external anal sphincter that are not innervated by the pudendal nerve, in contrast to the skeletal muscle fibers.…”

Pudendal Versus Caudal Block in Children Undergoing Hypospadias Surgery

“…None of the patients had defecation problems caused by the anal sphincter motor insufficiency after the pudendal nerve block. According to Shafik et al, 22 bilateral pudendal block does not eliminate electromyographic activity of the external anal or urethral sphincter at rest or during cough and does not visibly change the anal or urethral pressure. Transvaginal pudendal nerve block has potential complications such as vaginal mucosal laceration, hematoma, and infection (retropsoas and subgluteal abscess).…”

Smooth Muscle Precursor Cells Derived from Human Pluripotent Stem Cells for Treatment of Stress Urinary Incontinence

“…EMG activity has been used to assess sphincter function [30,43] and evaluate its regeneration in some studies involving autologous muscle progenitor cell and periurethral skeletal myofiber treatment [44,45].…”

“…SMCs have resting EMG, therefore, the recorded EMG activity includes that of both skeletal and smooth muscles [30]. EMG measurements can provide information about the integrity of innervation and the condition of neuromuscular junctions and myofibers [31].…”