The position of the patient does not adversely influence the results of the most clinically important measurements of anorectal function.

Anorectal physiological measurements were carried out in three groups of patients: Controls (n = 11), slow transit constipation (n = 21) and neuropathic faecal incontinence (n = 14) to examine whether the position of the patient influenced the result of tests of anorectal function. Measurements were made in both the conventional left lateral and the seated position. No significant differences were observed in the pressures within the anal canal at 2 cm from the anal verge, the usual site of maximum resting and maximum squeeze pressures, although, at 4 cm pressures were significantly different in the two positions. With all other tests including rectal compliance, anorectal inhibitory reflex and rectal sensation there was no significant difference due to position in any of the three clinical groups. We conclude that the left lateral position is generally satisfactory for measurement of the most clinically important aspects of anorectal function.