RECTUM

(Lat.), n. n. Reak'tusm(tu4m). Neut. of adj. rectus, straight. Gr., ap\6s. Fr.. r. Ger., Afterdarm. The portion of the large intestine extending from the sigmoid flexure to the anus. It pa es from opposite the left sacro-iliac synchondrosis, from left to right, to about the middle of the sacrum, whence it descends in the middle line to the anus. It is somewhat smaller above and dilates greatly near the anus. It is partially invested by the peritonaeum (cf. ME SO RECTUM), and has an external layer of longitudinal muscular fibres, beneath which are circular fibres (cf. SPHINCO, no; Oa, not; O8, whole; Th, thin; Tha, the; U, like oo in [s. 385] An Illustrated Encyclopædic Medical Dictionary, Cilt 4 — Frank P. Foster m (dev amı) – V (başı)