External Anal Sphincter

This sphincter encircles the internal sphincter but extends below it, ending subcutaneously. The lower edges of the external and internal sphincters can be distinguished on digital palpation. Although this sphincter is tonically contracted in the resting state, this contraction can be overcome with firm pressure (177). If the patient is asked to contract the anus during a digital assessment, the external sphincter can be felt to ensure contraction and closing of the anus tightly. However, because the muscle fibers are predominantly the slow-twitch type, a maximum contraction of the external sphincter can only be maintained for approx 1 minute(178).

Fecal continence is maintained by several factors, the relative importance of which has not been fully elucidated. Currently, the most important factor is the angulation between the rectum and the anal canal, which is maintained at a mean of 92° by continuous contraction of the puborectalis muscles, located above the external sphincter. Both sphincters have supportive roles in maintaining fecal continence (175), and their disruption can result in incontinence (see Subheading 10.6.2.).

Peripheral Neuropathy Natural Treatment Options

Peripheral Neuropathy Natural Treatment Options

This guide will help millions of people understand this condition so that they can take control of their lives and make informed decisions. The ebook covers information on a vast number of different types of neuropathy. In addition, it will be a useful resource for their families, caregivers, and health care providers.

Get My Free Ebook


Post a comment