Median sacral artery
Arteria sacralis mediana
A slender unpaired artery that leaves the back of the aorta just above its bifurcation and runs down the midline of the sacrum to the coccyx.
At a glance
- English
- Median sacral artery
- Latin (TA2)
- Arteria sacralis mediana
- System
- Artery
- Region
- Trunk
- Side
- Single, on the midline
About the median sacral artery
The median sacral artery, also known as the middle sacral artery, is a slim vessel that springs from the back of the abdominal aorta a short way above the point where the aorta divides into the two common iliac arteries, at about the level of the lower part of the third or the fourth lumbar vertebra. Although it is tiny, it is the true continuation of the aorta. In animals with tails it is a large vessel running into the tail; in humans it is reduced to a thin remnant.
From its origin it descends in the midline over the L4 and L5 vertebral bodies, then over the front of the sacrum and the coccyx. Over the lumbosacral junction the left common iliac vein crosses in front of it. It ends at the tip of the coccyx in a small cluster of vascular tissue called the coccygeal body. It runs with a pair of small veins that usually unite into one, which empties into the common iliac vein of the left side.
Along the way it gives small branches. Over the last lumbar vertebra it meets the iliolumbar artery's lumbar branch, and it may give a small fifth pair of lumbar arteries. Over the sacrum it joins the lateral sacral arteries on each side and sends twigs into the anterior sacral foramina. Minute branches also pass forwards to the back of the rectum.
Because it links the aorta with the lateral sacral branches of the internal iliac artery, it is one of the routes that keep blood flowing to the pelvis when an internal iliac artery is tied. It can also bleed during surgery in front of the sacrum, for example when the rectum is removed or when the lumbosacral disc is approached from the front.
Course and supply
- Arises from
- Arises from the posterior surface of the abdominal aorta just above its bifurcation, at about the third to fourth lumbar level.
- Ends in
- Ends at the tip of the coccyx in the coccygeal body, after joining the iliolumbar artery's lumbar branch and the lateral sacral arteries.
- Supplies
- Supplies the lower lumbar vertebrae, the sacrum, the coccyx and their contents through the sacral foramina, and the back of the rectum.
Anthromica
See the median sacral artery 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.
