The pathological assessment of the surgical specimens originating from the lower rectum and anal canal

摘要: The most profound investigation of the anorectal development was performed by Aigner et al. on 79 fetuses from ninth week postconceptionem [1]. According to their results during early prenatal life, muscular layers rectum and anal canal derive mesenchyme that accompanies endodermal part anorectum. inner circular layer precedes outer longitudinal seventh embryonic development. anlagen levator muscle external sphincter occur within surrounding mesenchymae. They are clearly separated each other they both show signs proliferative activity when get in contact with bundles smooth muscles deriving rectal wall. As a result ani grow larger (Fig. 1).