The median sacral artery (or middle sacral artery) is a small
artery that arises posterior to the
abdominal aorta
In human anatomy, the abdominal aorta is the largest artery in the abdominal cavity. As part of the aorta, it is a direct continuation of the descending aorta (of the thorax).
Structure
The abdominal aorta begins at the level of the thoracic d ...
and superior to its bifurcation.
Structure
The median sacral artery arises from the
abdominal aorta
In human anatomy, the abdominal aorta is the largest artery in the abdominal cavity. As part of the aorta, it is a direct continuation of the descending aorta (of the thorax).
Structure
The abdominal aorta begins at the level of the thoracic d ...
at the level of the bottom quarter of the
third lumbar vertebra. It descends in the middle line in front of the fourth and fifth
lumbar vertebrae, the
sacrum
The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30.
The sacrum situates at the upper, back part ...
and
coccyx, ending in the
glomus coccygeum (coccygeal gland).
Minute branches pass from it, to the posterior surface of the
rectum
The rectum is the final straight portion of the large intestine in humans and some other mammals, and the Gastrointestinal tract, gut in others. The adult human rectum is about long, and begins at the rectosigmoid junction (the end of the s ...
.
On the last lumbar vertebra it
anastomoses with the lumbar branch of the
iliolumbar artery; in front of the sacrum it anastomoses with the
lateral sacral arteries, sending offshoots into the
anterior sacral foramina.
It is crossed by the left
common iliac vein and accompanied by a pair of
venae comitantes; these unite to form a single vessel that opens into the left
common iliac vein.
Development
The median sacral artery is morphologically the direct continuation of the abdominal aorta.
It is
vestigial in humans, but large in animals with tails, such as the
crocodile
Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to inclu ...
.
See also
*
Lateral sacral artery
Additional images
File:Gray586.png, The iliac veins.
File:Gray587.png, Scheme of the anastomosis of the veins of the rectum.
File:Gray1120.png, The relations of the viscera and large vessels of the abdomen.
File:Slide12y.JPG, Median sacral artery
File:Slide2ERVA.JPG, Pelvic contents: male. Superior view. Deep dissection.
References
External links
* - "Posterior Abdominal Wall: Branches of the Abdominal Aorta"
* ()
{{Authority control
Arteries of the abdomen