Transverse colon
Organ supplied · Midgut Hindgut
Intraperitoneal on its mesocolon. The proximal two-thirds are midgut (middle colic, SMA) and the distal third is hindgut (ascending left colic, IMA); the embryonic boundary lies about two-thirds along, where the two systems meet in the marginal artery.
Traced from the start
Detail
- Proximal 2/3
- Middle colic (SMA) — midgut, vagal parasympathetics
- Distal 1/3
- Ascending branch of left colic (IMA) — hindgut, pelvic splanchnic (S2–S4) parasympathetics
- Referred pain
- Periumbilical (T10–T11) proximally, suprapubic (T12–L2) distally
When it goes wrong
Tumour on one side or the other of the SMA/IMA boundary
Extended right hemicolectomy (middle colic pedicle) for proximal lesions versus left hemicolectomy for distal lesions
Practise this structure
1 question in the bank tagged Large Bowel.