Vessel
Median sacral artery
Small posterior aortic branch over the sacrum
High-yield
Recognize the small unpaired posterior vessel near the aortic bifurcation. Its origin and relationship to the midline vary, so an L4 origin is an approximation.
Overview
The median sacral artery continues downward from the posterior aspect of the distal abdominal aorta. It approaches the front of the sacrum and coccyx, where its small branches communicate with other sacral vessels. Despite its name, its course can lie to either side of the exact midline.
Reference facts
- Origin
- Usually the posterior distal abdominal aorta near the iliac bifurcation; a shared origin with a lumbar artery is a recognized variant.
- Course
- Descends in front of the lower lumbar spine and sacrum toward the coccyx, often slightly off the midline.
- Branches
- Small lumbar, sacral and coccygeal branches, with occasional contributions to the posterior rectal region.
- Supplies
- Tissues over the lower spine, sacrum and coccyx; connections with lateral sacral vessels supplement this territory.
- Drains to
- Associated venous return is through median sacral veins, commonly toward the left common iliac vein; arteries themselves do not drain into veins directly.
Clinical correlation
Its position against the lumbosacral spine makes the artery a possible source of bleeding in spinal or deep pelvic surgery. Cadaveric studies document substantial variation in its exposed course.
Frequently asked questions
Where does the median sacral artery originate?
Usually the posterior distal abdominal aorta near the iliac bifurcation; a shared origin with a lumbar artery is a recognized variant.
What does the median sacral artery supply?
Tissues over the lower spine, sacrum and coccyx; connections with lateral sacral vessels supplement this territory.
Where does the median sacral artery drain to?
Associated venous return is through median sacral veins, commonly toward the left common iliac vein; arteries themselves do not drain into veins directly.
What are the branches of the median sacral artery?
Branches of the median sacral artery include the small lumbar, sacral and coccygeal branches, with occasional contributions to the posterior rectal region.