I — Anocutaneous line; 2 — Anal pecten; 3 — Skin; 4 — Anal columns; 5 — Anal sinuses; 6 — Anorectal junction; 7 — Rectal ampulla; 8 — Muscular layer; Muscular coat, longitudinal layer: 9 — Transverse folds of rectum; 10 — Solitary lymphoid nodules;
II — Levator ani; 12 — Internal anal sphincter; 13 — External
anal sphincter; 14 — Anal valves
