Methods of Studying Gastro-intestinal Motility: Large Intestine

The colon serves to absorb fluid and electrolytes, to mix its contents, to store its contents and to empty it in a controlled fashion. Motility, absorption and secretion closely interact to fulfil these functions. Tone, phasic contractions and ano-rectal closure are the main principles of colonic motility. They are controlled by the enteric nervous system. Colonic motility differs from that in other parts of the gut in that it is very slow and irregular, coordinated activity is rare and orad movements normal. The methods to study colonic motility are radiology which is largely abandoned, manometry with perfused catheters or ambulant with tip catheters, the use of the barostat, radioscintigraphy, marker transit, and electromyography. They all measure different aspects be it flow of colonic contents as in radioscintigraphy and marker transit or be it wall contractions as in manometry and electromyography or be it tone as in the barostat. They are therefore complimentary. So far, only marker transit in the colon and manometry in the ano-rectum are widely clinically used.