Iliolumbar vein
Vena iliolumbalis
A paired vein of the posterior abdominal wall that accompanies the iliolumbar artery and drains the iliac fossa and lower lumbar region.
At a glance
- English
- Iliolumbar vein
- Latin (TA2)
- Vena iliolumbalis
- System
- Vein
- Region
- Trunk
- Side
- Paired, left and right
About the iliolumbar vein
The iliolumbar vein is the companion vein of the iliolumbar artery. It drains blood from the back of the iliac fossa, the iliacus, psoas and quadratus lumborum muscles, and the lowest part of the vertebral column, including the fourth and fifth lumbar segments. It runs medially from the iliac fossa, deep to psoas major, towards the lumbosacral junction and ends by opening into the common iliac vein, or sometimes the internal iliac vein, of its own side.
In most people a single vein is present, though it may be doubled. As it passes medially, the obturator nerve runs across its superficial surface, a relation that matters when this nerve or the vein is being exposed in the region of the sacral promontory. Close to the spine the vein lies alongside the lumbosacral trunk and the sacral ala, and it communicates with the lower lumbar veins.
The vein is closely linked with the ascending lumbar vein, which often arises from or joins it. This connection makes the iliolumbar vein part of the network that allows blood from the pelvis and lower limbs to reach the azygos and hemi-azygos systems if the inferior vena cava is blocked.
Its practical importance is surgical. During anterior and lateral approaches to the lower lumbar spine, for example when disc space L4-L5 is exposed, the left common iliac vein must be retracted, and the iliolumbar vein tethering it is easily torn. Surgeons therefore look for it, and often tie and divide it, before moving the iliac vessels. Bleeding from this short, thin-walled vein can be brisk and awkward to control because it retracts into the deep tissues.
Course and drainage
- Begins at
- Formed in the iliac fossa and lower lumbar region from veins of the iliacus, psoas and quadratus lumborum and of the fourth and fifth lumbar segments.
- Drains into
- Passes medially deep to psoas major to open into the common iliac vein, occasionally the internal iliac vein.
- Drains
- Drains the iliac fossa, nearby posterior abdominal wall muscles and the lowest lumbar vertebral segments.
Anthromica
See the iliolumbar vein where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
