Blood supply:

Arterial supply
  • Single anterior spinal artery
  • Two posterior spinal arteries.
  • Radicular arteries originating from  (Inferior thyroid, Vertebral, Ascending pharyngeal, Intercostal arteries and Lumbar segmental).

Largest radicular artery artery of lumbar enlargement is called radicularis magna. Arises from lower intercostals, usually T10.

 

anterior spinal

The Anterior spinal artery supplies:

Anterior 2/3rds which includes:

•  The anterior horn

•  The lateral horn

•  The central gray

•  The basal part of the posterior horn

•  Anterior and lateral funiculi

The Posterior spinal artery posterior 1/3rd mainly the posterior funiculi


Spinal veins

 

Spinal veins drain in to the internal vertebral (epidural) plexus

Communications of epidural venous plexus:

  1. External vertebral plexus
  2. Intra cranial dural sinuses
  3. Inferior vena cava
  4. Azygous venous system
 

Lumbar cistern:

  • Enlarged subarachnoid space after cord termination.
  • Contains cauda equina.
  • Usual site for lumbar puncture.

 


Organization of Spinal Nerves
  • There are 31 pairs of spinal nerves.
  • Each spinal nerve is formed by union of the dorsal (sensory) root ; and a ventral (motor) root .
  • It divides into dorsal and ventral rami .

Functional components

  1. General somatic efferents (GSE)- motor to skeletal muscle.

  2. General visceral efferent (GVE) - autonomic

  3. General somatic afferent (GSA) -sensory to somatic structures.
  4. General visceral afferent (GVA) - sensory to visceral structures.