Figure 1.

Neuronal innervation of the lower colon track in HSCR and non-HSCR patients. Schematic representation of extrinsic AChE⁺ nerve fiber innervation (A). Anatomically, extrinsic innervation derived from sacral roots S2–4 is limited to the rectosigmoid and does not reach the descending colon. Rec (1), rectum; SC (2), sigmoid colon; DC (3), descending colon; AChE, acetylcholinesterase; S2–4, sacral roots S2–4. Cryosections (5µm) of aganglionic and ganglionic colonic tissue from HSCR and non-HSCR patients showing anti-AChE immunohistochemistry and anti-ß3 tubulin immunofluorescence (B). Five different colonic tissue types were distinguished, and each showed different expression of ENS (aganglionic versus ganglionic) and mucosal nerve fiber innervation. Scale bar: 50µm. IHC, immunohistochemistry; IF, immunofluorescence; ENS, enteric nervous system.