Anorectal manometry requires a different design of catheter, depicted in Fig. 4.1 . A set of 10 closely spaced sensors spans a length of 6 cm. It simultaneously captures pressure data from the rectum, anal and atmospere. A second array of sensors, located close to the tip, captures intrarectal pressure. A balloon attached to metal rings (arrow) serves to elicit the rectoanal inhibitory reflex, and also is used for assessment of rectal sensation.