1. SPINAL CORD ANATOMY

2. General Characteristics Approx. ½ meter in length. Approx. ½ meter in length. Varies from 1 to 1.5 cm in diameter. Varies from 1 to 1.5 cm in diameter. Enlargements: Enlargements:Cervical: C3 – T1. Lumbar region: L1 – S2.

3. General Characteristics Conus medullaris: Conus medullaris: Ends at about the level of L2. Cauda equina. Cauda equina. Filum terminale: Filum terminale: Thin filament of meningeal tissue extending from conus medullaris to the coccyx.

4. Spinal Nerves 08 cervical. 08 cervical. 12 thoracic. 12 thoracic. 05 lumbar. 05 lumbar. 05 sacral. 05 sacral. 01 coccygeal. 01 coccygeal.

5. Plexuses Cervical: Cervical: C1 – C4. Brachial: Brachial: C5 – T1. Lumbosacral: Lumbosacral: L1 – S4.

6. Cross-Sectional Anatomy Central canal. Central canal. Gray matter: Gray matter:“H”-shaped. White matter. White matter.

7. Gray Matter Horns are equivalent to CNS nuclei. Horns are equivalent to CNS nuclei. Posterior (dorsal) horns: Posterior (dorsal) horns: Receive incoming sensory fibers. Anterior (ventral) horns: Anterior (ventral) horns: Site of cell bodies of alpha motor neurons to skeletal muscle fibers. Lateral horns: Lateral horns: Located only in thoracic and upper lumbar region: Site of cell bodies of ANS motor neurons.

9. White Matter Columns are referred to as funiculi. Columns are referred to as funiculi. Columns consist of myelinated tracts. Columns consist of myelinated tracts. Posterior (dorsal) columns. Posterior (dorsal) columns. Anterior (ventral) columns. Anterior (ventral) columns. Lateral columns. Lateral columns.

10. Commissures White: White: Anterior and posterior. Gray: Gray: Anterior and posterior.

11. Spinal Nerves Dorsal rootlets. Dorsal rootlets. Dorsal root: Dorsal root: Carries afferent fibers. With dorsal root ganglion: Location of cell bodies of afferent neurons. Ventral root: Ventral root: Carries efferent fibers. No associated ganglion.

12. Spinal Nerves Spinal nerve carries a mixture of fibers: Spinal nerve carries a mixture of fibers: Both afferent and efferent. Both visceral and somatic. Proprioceptive.

13. Primary Rami Dorsal (posterior): Dorsal (posterior): To expaxial musculature (deep back muscles) and skin on either side of dorsum of back. Ventral (anterior): Ventral (anterior): To hypaxial musculature (rest of skeletal musculature including muscles of limbs) and rest of skin.

14. Autonomic Rami White ramus communicans: White ramus communicans: Carries pre-ganglionic sympathetic fibers from lateral horns of central gray of spinal cord (thoracolumbar regions). Gray ramus communicans: Gray ramus communicans: Carries post-ganglionic sympathetic fibers from paravertebral ganglia back to spinal nerve.

16. Meniniges Epidural space. Epidural space. Dura mater: Dura mater: Tough outer layer. Subdural space. Subdural space. Arachnoid. Arachnoid.

17. Meniniges Subarachnoid space: Subarachnoid space: Contains CSF. Pia mater: Pia mater: Delicate innermost layer. Denticulate ligaments. Denticulate ligaments.