Median sacral artery
The median sacral artery is a narrow unpaired vessel that arises from the posterior aspect of the abdominal aorta. It usually originates immediately superior to the abdominal aortic bifurcation, at the level of the fourth lumbar vertebra.
The median sacral artery is located roughly in the midline. It runs inferiorly over the anterior aspect of the lumbar vertebrae and sacrum towards the apex of the coccyx. On its course, it provides several small branches that supply the structures of the pelvis. These structures include: lumbar vertebrae (L4, L5), sacrum, coccyx and rectum.
This article will discuss the anatomy and function of the median sacral artery.
|Branches||Arteriae lumbales imae, lumbar branches, lateral sacral branches|
|Supply||Lumbar vertebrae (L4, L5), sacrum, coccyx, anorectal junction, posterior part of the rectum|
Origin and course
The median sacral artery arises from the posterior aspect of the distal part of the abdominal aorta. Usually, it originates immediately above the aortic bifurcation, at the level of the superior part of L4 vertebra.
The median sacral artery usually runs at the midline, descending across the ventral aspect of the distal part of the lumbar spine and sacrum, towards the apex of the coccyx. The artery is usually accompanied by the same-named vein that typically lies anterior to it. It terminates at the coccygeal body, near its apex.
Branches and supply
The median sacral artery provides several small branches that supply the structures of the pelvis and form anastomoses with the other arteries from the same region. The median sacral artery supplies the lumbar and sacral vertebra, coccyx, anorectal junction and posterior part of the rectum.
- The parietal lumbar branches arise at the level of the last two lumbar vertebrae. These branches form anastomotic networks with the same-named branches of the iliolumbar artery.
- The small lumbar artery (arteria lumbalis ima) arises at the level of L5. It runs via the anococcygeal ligament to supply the anorectal junction.
- The lateral sacral branches arise inferior to the sacral promontory. These branches anastomose with the lateral sacral arteries of the internal iliac artery.
- Additionally, other small branches can arise from the median sacral artery to supply the posterior part of the rectum. These branches usually anastomose with the superior rectal and middle rectal arteries.
Learn more about the arteries of the sacrum with our articles, videos, labeled diagrams and quizzes.