A cinefluoroscopic study of the caecal base of the horse

Abstract

Separate mechanisms exist for transporting ingesta and gas from the caecum to the colon. Both involve the isolation of the cranial part of the base by a constriction cranial to the ileal papilla. This involves elevation of the floor of the base and is associated with dilation of the caecocolic ostium which at other times is closed. Contraction of the ingesta-filled cranial compartment expels some material to the colon but allows most to return to the body. Contractions which discharge gas do not result in the passage of significant amounts of ingesta. The gas expelled is at once hurried through much of the ascending colon. Any considerable reflux to the caecum is prevented by the sigmoid configuration of the caecocolic junction.