Spinal Cord

Question 1

Spinal Cord

Answer 1

Communication between CNS and PNS
Reflex center
Extends from foramen magnums to L1 or L2 of vertebrae
Conus Medullaris - distal tapered end of spinal cord
Cauda equina - collection of spinal nerve roots extend inferior of spinal cord (horse tail)
Filum terminale - Extension of Pia mater from conus medullaris anchoring to the posterior surface of coccyx

Question 2

Gross anatomy

Answer 2

Cervical enlargement - C5-T1, Brachial plexus, innervate upper limb
Lumbosacral enlargement - L1-S3, lower limb innervation, lumbar and sacral plexuses
Protected by bones and meninges
Denticulate ligaments attach to Pia mater

Question 3

Meningeal Spaces

Answer 3

Epidural - actual space, filled with epidural fat and venous plexus
Subdural - Potential space
Subarachnoid - Actual space; location of CSF

Question 4

Spinal Nerve anatomy

Answer 4

Dorsal horn - sensory axons, interneurons
Dorsal root - sensory axons
Dorsal root ganglion - sensory neuron cell bodies
Ventral horn - lower motor neuron cell bodies
Ventral root - lower motor axons
Spinal nerve - mixed motor and sensory axons
Ventral rami - motor and sensory axons to muscles and skin of anterior trunk and limbs
Dorsal rami - Motor and sensory axons to muscles and skin of the back
Sensory Afférent, Motor Efferent

Question 5

Cross section of spinal cord

Answer 5

Cell bodies of motor neurons in ventral horn
Motor neurons axons through ventral root — spinal nerve — ventral or dorsal ramus — named nerves to effector
Cell bodies of sensory neurons in dorsal root ganglia
Axons enter through dorsal ventral ramus — spinal nerve — dorsal root — synapse with interneuron in dorsal horn
White matter consist largely of myelinated axons organized into tracts or fasciculi

Question 6

Orientation

Answer 6

Find dorsal root ganglion, will be located on the posterior/dorsal side
Ventral (anterior) median fissure, and dorsal (posterior) median sulcus
Fissure deeper and anterior
Sulcus shallow and posterior

Question 7

Homunculus

Answer 7

Anterior cerebral back and trunk, lower limb
Middle cerebral head/face, upper limb
Post-central gyrus of parietal lobe provides sensory for upper limb
Pre-central gyrus of frontal lobe provides motor for upper limb
Post central gyrus of parietal lobe proved sensory for middle back
Precentral gyrus of frontal lobe provides motor for middle back