A diagnostic test that measures the pressure, sensation, reflexes, and coordination of the rectum and anal sphincter muscles.

Mechanism:

A thin, flexible catheter with sensors is inserted into the rectum.

Records resting and squeeze pressures, reflex relaxation, and rectal sensation during balloon inflation.

Common Uses / Indications

Chronic constipation → assess outlet obstruction or dyssynergic defecation.

Fecal incontinence → evaluate sphincter weakness or sensory dysfunction.

Hirschsprung disease (children) → absence of the rectoanal inhibitory reflex (RAIR).

Pre- and post-surgical evaluation of anorectal function.

What It Measures

Resting pressure (internal anal sphincter function)

Squeeze pressure (external anal sphincter strength)

Rectoanal inhibitory reflex (RAIR)

Rectal sensation & compliance