Hindgut
Territory · Distal 1/3 transverse → pectinate Suprapubic pain
Supplied by the IMA: distal third of the transverse colon, descending and sigmoid colon, rectum and anal canal above the pectinate line. Visceral afferents run with the lumbar splanchnics to L1–L2 and pain is felt suprapubically; below the pectinate line the anal canal is somatic (pudendal) and supplied by the inferior rectal artery.
Traced from the start
Detail
- Extent
- Distal third of the transverse colon to the pectinate line
- Arterial supply
- Inferior mesenteric artery (L3)
- Referred pain
- Suprapubic (L1–L2, lumbar splanchnic nerves)
When it goes wrong
Diverticulitis or sigmoid volvulus
Suprapubic or left lower quadrant visceral pain that localises once the peritoneum is involved
Lesion below the pectinate line (anal fissure, thrombosed external haemorrhoid)
Sharp somatic pain via the inferior rectal (pudendal) nerve, whereas internal haemorrhoids above the line, in IMA territory, bleed painlessly
Practise this structure
1 question in the bank tagged Hindgut.