Normal tarm-diameter: Store vs. små tarm dimensioner

SegmentTom diameterDistenderet diameter
Lille tarm2–3 cm (0,8–1,2 in)3–4 cm
Stor tarm (Colon)4–5 cm (1,6–2 in)8–10 cm (3,1–3,9 in)
RectumKollaberet4–6 cm (ved ampulla)

Variabilitet: kropstype, alder, distensionstilstand, billedgivende modalitet (CT vs. US vs. MRI). Patologisk dilatation: lille tarm >3 cm, colon >6 cm (caecum >9 cm = volvulus-risiko).

Irritabel tyktarm (IBS)