The Lumbar Spine Masterclass, Part 6
We have covered a lot of material along the way. Feel free to go back and review to help pull everything together. Part 1 = bones of the lumbar spine. Part 2 = the miraculous disc. Part 3 = ligaments of the lumbar spine . Part 4 = the fascinating muscles. Part 5 = the nerves of the lumbar spine.
Last, but not least, is the vasculature/ blood supply, to and from the lumbar spine. The arteries and veins which supply this region are not commonly discussed.
Taken from: https://www.sciencedirect.com
The arteries for the lumbar spine come straight off the aorta. The vessels travel along each nerve and enter the intervertebral foramen. The artery has two choices; it can stay with the nerve all the way to the end of its course or it can diverge from the nerve root. The diverging artery will the attach to either, or both, the anterior spinal artery or the posterior spinal arteries. If the artery takes the first option, stays with the nerve all the way to the end of its course, it is called a radicular artery. If option number two is more appealing, the artery supplies the nerve but the takes off and heads for the anterior/ posterior spinal arteries, it is called a medullary artery. The spinal arteries, anterior and posterior, get most of their blood through medullary arteries. The initial branch off the basilar artery that starts the anterior and posterior arteries is not sufficient to supply the entire spinal cord. Therefore, medullary arteries come in to supplement the blood supply to the spinal cord. There is one large medullary artery that arrives just above the lumbar spine. It is called the Great Medullary Artery or the Artery of Adamkiewicz. It typically enters through the 9th - 12th intercostal arteries and attaches to the anterior spinal artery, helping to supply the lower ⅓ of the spinal cord.
Taken from: https://thejns.org
There are branches off the radicular and medullary arteries at each level, anterior and posterior spinal canal branches. Those supply the vertebral bodies, the ligaments and muscles at each level.
Taken from: https://thejns.org
The lumbar veins have a simple path back to the heart. Like most parts of the body, the veins and arteries run together. The basivertebral veins leave the vertebral bodies. These veins drain mostly to the posterior of the vertebral body into the anterior internal vertebral venous plexus. At every level, the anterior internal vertebral venous plexus sends off branches to the ascending lumbar vein. The ascending lumbar vein then communicates with the common iliac vein, inferiorly. Superiorly, the ascending lumbar vein attaches to the azygous vein, on the right and hemiazygous vein on the left. Around T12, these veins come together with some other and join the superior vena cava.
That is all, and more, that I know about the lumbar spine. It is amazing how much I actually knew to write this huge post, my biggest one ever! But I did get some help from Wikipedia, Magee’s Orthopaedic Physical Assessment, 5th edition, Bogduk’s 3rd edition of Clinical Anatomy of the Lumbar Spine and Sacrum as well as from the Orthopaedic Division’s Theory II manual and Level II Lower clinical manual and lastly my own brain.
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