Nervous System: The Spinal Cord

Spinal cord

Part of the nervous system that extends from the foremen magnum to the second lumbar vertebra (L2). Conveys sensory impulses to the brain and integrates reflexes

Cervical and lumbar englargements

Areas of the spinal cord larger in diameter than the rest

Conus medullaris

Cone-like region that makes up the inferior tip of the spinal cord

Cauda equina

Spinal nerves that originate and extend inferiorly from the lumbo-sacral enlargement and conus medullaris

Dura, arachnoid, pia

Spinal meninges

Dura mater

Superficial spinal meninge, tough and protective

Arachnoid mater

Middle spinal meninge, thin and wispy with lots of blood vessels

Pia mater

Deepest spinal meninge, thin and delicate and bound tightly to surface of brain and spinal cord

Epidural

Space between the walls of vertical canal and dura mater

Subdural

Space between dura mater and arachnoid mater, contains serous fluid

Subarachnoid

Space between arachnoid and pia mater, contains CSF and blood vessels, site of spinal taps

Posterior horn

Part of spinal gray matter that contains sensory axons

Anterior horn

Part of spinal cord gray matter that contains motor neuron bodies

Lateral horn

Part of spinal gray mater that contains autonomic neuron bodies

Dorsal/posterior root

Spinal nerve root that conducts signal INTO spinal cord (sensory input)

Ventral/anterior root

Spinal cord root that conducts signal AWAY from spinal cord (motor output)

8, 12, 5, 5, 1

Number of cervical, thoracic, lumbar, sacral, and coccygeal spinal nerves