Frenulum of ileal orifice

The frenulum of ileal orifice (frenulum ostii ilealis; plural frenula of the ileal orifice) consists of narrow mucosal folds located at the two extremities of the ileal orifice, where the ileocolic and ileocecal lips meet and merge. At both the anterior (left) and posterior (right) ends of the orifice, the lips coalesce and continue for a short distance as delicate membranous ridges surrounding the terminal part of the ileal canal. These folds or frenula serve as points of attachment that anchor the lips of the ileal orifice to the adjacent intestinal wall, thereby helping to maintain the shape and stability of the valvular apparatus. The anterior frenulum is usually broader and associated with the rounded anterior end of the ileal orifice, whereas the posterior frenulum corresponds to the narrower, more pointed posterior end of the orifice.

Structurally, the frenula are formed by continuations of the mucosal and submucosal tissues of the valve and contribute to the coordinated opening and closing movements of the ileal orifice during intestinal transit. Although they do not possess an independent sphincteric function, the frenula help preserve the anatomical configuration of the ileal orifice and support its role in regulating the passage of intestinal contents from the ileum into the cecum.