Spinal cord-Blood supply

Blood supply of spinal cord explained in brief with clinical application

1. Blood supply of spinal cord

2. ARTERIAL SUPPLY Anterior spinal artery Two posterior spinal arteries Segmental arteries

3. Anterior spinal artery ORIGIN: formed by union of two small spinal b ranches of right and left vertebral arteries in the upper cervical canal. COURSE: It runs caudally in the anterior median fissure. Joins with the fellow of the opposite side to form anterior arterial trunk. TERMINATION : filum terminale SUPPLIES : Anterior two third of the cord

4. Anterior spinal artery syndrome It occurs due to occlusion (thrombosis or compression) of the anterior spinal artery Therefore, resulting in a)Motor symptoms- due to involvement of corticospinal tracts and anterior grey columns b)Bilateral loss of pain and temperature sensation due to ischemia of spinothalmic tracts

5. P osterior spinal arteries ORIGIN : Branched from either 1 . Vertebral 2.Posterior inferior cerebellar arteries

6. COURSE: Runs down in the posterolateral sulcus divides into two collateral arteries medial and lateral along the posterior nerve roots. Thus, there are 5 longitudinal arteries around the spinal cord. These arteries reinforced by the segmental arteries to form 5 longitudinal arterial trunks These communicate around the cord forming pial plexus, the arterial vaso -corona/ arteriae coronae . The arteriae coronae give peripheral branches which supply the superficial regions of the cord SUPPLIES :Posterior one third of the cord

7. Segmental arteries They reach the spinal cord as anterior and posterior radicular arteries along the corresponding roots of the spinal nerves respectively and nourish the nerve roots. Branches of Deep cervical, Ascending cervical, Intercostal and Lumbar

8. Anterior arterial trunk- formed by union of two anterior spinal arteries arising from vertebral arteries and a branch of Arteria magna Posterior spinal trunk- formed by two posterior spinal arteries and posterior radicular arteries

9. ANTERIOR RADICULAR ARTERIES: Larger and less in number. T1 and T11 are very large – Arteria radicularis magna {Artery of adamkiewicz } POSTERIOR RADICULAR ARTERIES: Smaller and more in number. Importance : radilcular /segmental arteries are more important in the vascular supply of the cord because the are end arteries and therefore, if anyone of them is blocked the area supplied by that particular artery will be damaged.

10. Clinical correlation The artery of T11 spinal segment ( arteria radicularis magna) is remarkably large. A fracture of vertebra involving this artery leads to softening of several segments of the cord The artery of T1 spinal segment anastamoses with other arteries in a valvular fashion so that its supply is directed only downwards. Therefore C8 segment is most affected. •T1,T4 and L1 segments -- the meeting places of different major arteries are vulnerable to ischemic necrosis.

11. VENOUS DRAINAGE • Two median longitudinal- one in the anterior median fissure another in posteromedian sulcus • Two anterolaterlal – one on either side posterior to the anterior nerve roots • Two posterolateral -one on either side posterior posterior nerve roots

12. Drain below through internal vertebral venous plexus into the vertebral posterior intercostal, lumbar, and lateral sacral veins. And internal vertebral venous plexus communicates above with the basilar venous plexus .

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