Sphincter length was determined by the position of the puborectalis sling. Defects in the external anal sphincter were defined at each level and recorded in degrees. Cylindric longitudinal images of the endoanal scans were created by a three-dimensional-representation software package. Manometry was performed by a pull-through technique. The mean age was 39 years for males and There was no significant difference in overall sphincter length or in the internal anal sphincter length as a percentage of overall sphincter length between genders.
Endoanal ultrasound is now regarded as the gold standard for evaluating anal sphincter pathology in the investigation of anal incontinence. The advent of three-dimensional ultrasound has further improved our understanding of the two-dimensional technique. Endoanal ultrasound requires specialised equipment and its relative invasiveness has prompted clinicians to explore alternative imaging techniques. Transvaginal and transperineal ultrasound have been recently evaluated as alternative imaging modalities. However, the need for technique standardisation, validation and reporting is of paramount importance. We conducted a MEDLINE search to February and critically reviewed studies using the three imaging techniques in evaluating anal sphincter integrity.
Ultrasound imaging of the anal sphincter complex: a review
To evaluate anal sphincter anatomy using three-dimensional ultrasonography 3-DAUS in incontinent women with vaginal delivery, correlate anatomical findings with symptoms of fecal incontinence and determine the effect of vaginal delivery on anal canal anatomy and function. A control group comprising asymptomatic nulliparous was included. Of the 62, 49 had fecal incontinence and 13 were asymptomatic.
In humans , the anus from Latin anus meaning "ring", "circle"   is the external opening of the rectum. Two sphincters control the exit of feces from the body during an act of defecation , which is the primary function of the anus. These are the internal anal sphincter and the external anal sphincter , which are circular muscles that normally maintain constriction of the orifice and which relaxes as required by normal physiological functioning.