The size of the anterior spinal artery in relation to the arteria medullaris magna anterior in humans.
We studied the anterior spinal artery (ASA) in 25 cadaveric human spinal cords to determine the cross-sectional area of the ASA cephalad and caudal to the entry of the arteria medullaris magna anterior (AMMA). Spinal cords were removed en bloc and latex was injected into the AMMA. The preparations were then fixed in formalin, embedded in paraffin, sectioned, mounted, and stained with hematoxylin and eosin. The diameter and cross-sectional area of the ASA 1 cm above and 1 cm below the entry of the AMMA were measured. The mean radius of the ASA above the entry of AMMA was 0.14 +/- 0.03 mm compared to 0.28 +/- 0.05 mm below the entry of the AMMA (P < 0.001). According to Poiseuille's equation, the resistance to blood flow in the ASA cephalad to the AMMA would be 14.8 times greater than the resistance to blood flow caudal to the AMMA. This resistance could affect the distribution of blood flow in the distal spinal cord whenever flow in the AMMA or distal ASA is altered.
Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota 55905, USA.
T
T
Zhang
L
L
Harstad
J E
JE
Parisi
M J
MJ
Murray
D000328:Adult; D001158:Arteries / Q000033:anatomy & histology; D005260:Female; D006801:Humans; D008297:Male; D013116:Spinal Cord / Q000098:blood supply*