anal sphincter


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Related to anal sphincter: hemorrhoid, sphincter ani, Sphincter ani externus muscle

anal sphincter

[′ān·əl ′sfiŋk·tər]
(anatomy)
Either of two muscles, one voluntary and the other involuntary, controlling closing of the anus in vertebrates.
References in periodicals archive ?
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 injection of Botox can be used to temporarily paralyze the anal sphincter and relieve spasms.
Nineteen percent of women who had vaginal delivery and anal sphincter laceration met the criteria for AI according to the EPIQ.
Adding to the problem, MS can make the external anal sphincter stiff and spastic so it won't relax on cue.
The anal ducts may penetrate the internal anal sphincter and may extend into perianal fat.
Research conducted in the UK demonstrated that major perineal tears, including anal sphincter injuries, were missed on clinical examination by midwives and doctors (Andrews, Sultan, Thakar, & Jones, 2006; Groom & Paterson-Brown, 2002).
However, monopolar stimulation induced leg and anal sphincter contractions that were not seen with bipolar stimulation.
In the upper motor neuron or reflex bowel, the anal sphincter remains tight and bowel movement will occur on a reflex basis.
The occurrence of FHC after only 26 weeks can be explained by the progressive closure of the anal sphincter that commences after 22 weeks.
Researchers have identified a number of obstetric interventions that significantly increase a woman's risk of suffering anal sphincter tears during birth.
26,27) Operative delivery remains a major modifiable risk factor for anal sphincter injury in primiparous women.
In the setting of dyssynergic defecation, which accounts for roughly half of all cases of chronic constipation, the pathophysiology involves a lack of coordination between the pelvic floor muscles and anal sphincter, explained Dr.