Transcript Neuro 03 Spinal Cord Student

SPINAL CORD ANATOMY
General Characteristics
Approx. ½ meter in length.
 Varies from 1 to 1.5 cm in diameter
 Enlargements:

Cervical:
C3 – T1
Lumbar region:
L1 – S2
General Characteristics

Conus medullaris:
Ends at about the level of L2.
Cauda equina.
 Filum terminale:

Thin filament of meningeal tissue extending
from conus medullaris to the coccyx.
Spinal Nerves
08 cervical
 12 thoracic
 05 lumbar
 05 sacral
 01 coccygeal
 Numbering system

Plexuses

Cervical:
C1 – C4

Brachial:
C5 – T1

Lumbosacral:
L1 – S4
Meninges
Epidural space
 Dura mater

Tough outer layer
Subdural space
 Arachnoid

Meninges

Subarachnoid space
Contains CSF

Pia mater
Delicate innermost layer
Spinal Cord Cross-Sectional
Anatomy
Central canal
 Gray matter

“H”-shaped

White matter
Gray Matter
Forms regions known as horns.
 Equivalent of CNS nuclei.
 Posterior (dorsal) horns:

Receive incoming sensory fibers.

Anterior (ventral) horns:
Site of cell bodies of alpha motor neurons to
skeletal muscle fibers.
Gray Matter

Lateral horns:
Located only in thoracic and upper
lumbar regions.
Site of cell bodies of ANS motor neurons.
White Matter
Forms longitudinal columns (funiculi).
 Consists of myelinated tracts.
 Posterior (dorsal) columns.
 Anterior (ventral) columns.
 Lateral columns.

Commissures

White:
Anterior and posterior.

Gray:
Anterior and posterior.