المشرج

thumb | right | alt=Coronal section through the anal canal. (Symington.) B. Cavity of urinary bladder. V.D. Ductus deferens. S.V. Seminal vesicle. R. Second part of rectum. A.C. Anal canal. L.A. Levator ani. I.S. Sphincter ani internus. E.S. Sphincter ani externus. | Coronal section through the anal canal. (Symington.) B. Cavity of urinary bladder. V.D. Ductus deferens. S.V. Seminal vesicle. R. Second part of rectum. A.C. Anal canal. L.A. Levator ani. I.S. Sphincter ani internus. E.S. Sphincter ani externus. A proctodeum is the back ectodermal part of an alimentary canal. It is created during