anal sphincter

(redirected from External anal sphincter)
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ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.anal sphincter - the sphincter muscle of the anus
anus - the excretory opening at the end of the alimentary canal
anatomical sphincter, sphincter, sphincter muscle - a ring of muscle that contracts to close an opening
musculus sphincter ani externus - an external ring of striated muscle surrounding the anus
musculus sphincter ani internus - an internal ring of smooth muscle formed by circular fibers of the rectum
References in periodicals archive ?
Moreover, low-lying staple lines may incorporate the internal and/or external anal sphincter and cause damage.
In this study, perineal body thickness, anal sphincter maximum squeezing pressure, mean resting pressure (MRP), external anal sphincter defect (EASD) and sphincter angle were evaluated.
Reflex relaxation of the pelvic floor is suppressed with pain from anal fissures or inflamed haemorrhoids, causing the external anal sphincter to become hypertonic.
An iatrogenic third or fourth degree tear was given and practical training included identification and repair of torn internal anal splincters (IAS) and external anal sphincters (EAS) according to the RCOG guidelines.
Moreover, the paradoxical contraction of the external anal sphincter during straining to defecate was electromyographically evidencied.
The researchers included 133 patients who were experiencing chronic fecal incontinence of at least two episodes per week and who had an external anal sphincter defect of less than 60 degrees.
Needle electrodes are placed at the external anal sphincter, the gluteus medius and maximus, the adductor longus, the tibialis, and the gastrocnemius muscles.
While 60% of study participants had intact external and internal anal sphincters seen on endoanal ultrasound, and 30% had an isolated external anal sphincter defect only, the remaining 10% of participants had either defects in both sphincters or such profound distortion of the sphincters that the anatomy was not interpretable.
The external genitalia and the urogenital diaphragm are found within the urogenital triangle, while the anal triangle is composed of the centrally placed anal canal encircled by the external anal sphincter and flanked laterally and posteriorly by the ischiorectal fossae (Figure 3).
This decrease in IAS is associated with an increase in external anal sphincter (EAS) activity, also known as the rectoanal inhibitory reflex (RAIR).[1]
The external anal sphincter remains tight due to spasticity of the pelvic floor; this promotes stool retention.

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