NEUROANATOMY
SPINAL CORD
External features of the spinal cord
• The spinal cord is also called the spinal medulla (Medulla
spinalis).
• Location: it is located in the vertebral canal
• It occupies only the upper two-thirds of the vertebral canal.
• Extent: upper border of C1-lower border of L1
• Termination
Fig. 1 Spinal cord: beginning and termination
Fig. 2 Shows termination of spinal cord, conus
medullaris and cauda equina
• Coverings
Subrachnoid space
Arachnoid trabeculae
Pia mater
Posterior spinal arteries
Ligamentum denticulatum
Anterior root
Posterior root
Spinal ganglia
Arachnoid mater
Dura mater
Recurrent meningeal branches of
spinal nerves
Fig. 3 Meninges covering parts of the thoracic region of the spinal cord (posterior view)
Extension of meninges
• Ligamentum
denticulatum
Fig. 4 Ventral surface of the spinal cord showing Ligamentum denticulatum
• Filum terminale
Fig. 5 Lower part of spinal cord
showing filum terminale
• Spinal cord segments/regions
Regions: cervical, thoracic, lumbar, sacral and coccygeal
regions
Segment: 31 segments
o Cervical: 8
o Thoracic: 12
o Lumbar: 5
o Sacral: 5
o Coccygeal: 1
Fig. 6 Basic organization of spinal nerve and spinal cord segment
Blood supply of the spinal cord
➢ Spinal branches of the vertebral artery
• Anterior spinal artery
• Posterior spinal artery
➢ Radicular arteries derived from segmental arteries
Fig.7 Arterial supply of the spinal
cord, anterior surface and arteries.
Fig.8 Arterial supply of the spinal cord, poterior surface and
arteries.
Fig.9 Blood vessels around the spinal cord
Venous drainage of the spinal cord
• Anteromedian longitudinal venous channel
• Posteromedian longitudinal venous channel
• Anterolateral longitudinal venous channel (paired)
• Posterolateral longitudinal venous channel (paired)
Clinical anatomy of the spinal cord
• Quadriplegia is the paralyses of all four limbs
• Paralyses of respiratory muscles
• Erb’s paralysis results from injury to spinal nerves C5 and C6, this
results in
• loss of abduction of shoulder
• loss of flexion of elbow
• loss of supination
• loss of extension of wrist
• Klumpke’s paralysis results from injury to spinal nerves C8
and T1, paralysis of intrinsic muscles of the hand caused claw
hand.
• Paraplegia is the paralyses both the lower limbs. It is caused
by injury to spinal cord between T2 and L1