Which diagnostic test is best described to quantify anorectal sensation and pressures and anal canal length?

Which diagnostic test is best described to quantify anorectal sensation and pressures and anal canal length?

• A. Defecography
• B. Anal electromyography
• C. Anorectal manometry
• D. Endoanal ultrasound

Answer: (C)

Anorectal manometry is the test that quantifies sensation, pressures, and the length of the anal canal. It uses a pressure-sensor catheter inserted into the rectum and anal canal to record resting anal canal pressure, the peak pressure during a deliberate squeeze (external anal sphincter function), and responses to provocative maneuvers like coughing. Sensory function is tested by distending a rectal balloon and noting the volumes at which the patient first senses fullness, feels an urge to defecate, and reaches maximum tolerance. By noting where elevated pressures begin and end along the catheter, the anal canal length can be estimated. This combination of measurements specifically addresses both sensory thresholds and the pressure profile of the anal sphincters, plus the canal length, which other diagnostic tests do not provide in a single study. Defecography visualizes defecation dynamics, anal electromyography measures electrical activity of muscles rather than pressures or sensation, and endoanal ultrasound images anatomy of the sphincters rather than functional data.

Anorectal manometry is the test that quantifies sensation, pressures, and the length of the anal canal. It uses a pressure-sensor catheter inserted into the rectum and anal canal to record resting anal canal pressure, the peak pressure during a deliberate squeeze (external anal sphincter function), and responses to provocative maneuvers like coughing. Sensory function is tested by distending a rectal balloon and noting the volumes at which the patient first senses fullness, feels an urge to defecate, and reaches maximum tolerance. By noting where elevated pressures begin and end along the catheter, the anal canal length can be estimated. This combination of measurements specifically addresses both sensory thresholds and the pressure profile of the anal sphincters, plus the canal length, which other diagnostic tests do not provide in a single study. Defecography visualizes defecation dynamics, anal electromyography measures electrical activity of muscles rather than pressures or sensation, and endoanal ultrasound images anatomy of the sphincters rather than functional data.