Spinal Tracts, Decussations, and Pathology

How many spinal nerves are there in total?

"31 Falvors of Baskin Robbins!" - 8 cerebral - 12 thoracic - 5 lumbral - 5 sacral - 1 saccral

Where do you do lumbar punctures?

"L3 to L5 to keep the cord alive!"

Tabes dorsalis

- Argyll pupils constrict to accommodation but not light - No DTRs on exam, Romberg(+)

Dorsal Column (nerves, synapse, decussation)

- Ascends to medulla oblongata and synpases in cuneatus (or gracilis) - Decussates in medulla => synpases in VPL of thalamus - Goes to sensory cortex

Syringomyelia

- Chiari I - B/l loss of pain/temp in cape distribution

Dorsal column and spinothalamic

- DCLM: vibration, proprioception, LE in fasciculus gracilis - Spinothalamic: pain, temp, head is medial

Ventricles... what connects them?

- Foramen of Monroe connects 1/2 and 3 - Aqueduct connects 3 and 4 - Luschka is lateral - Magendie is medial

Poliomyelitis

- LMN lesions only - Flaccid paralysis

Vitamine B12 deficiency (or E)

- Loss of proprioception, vibration and voluntary movement - Ataxic gait, paresthesias

Lateral corticospinal tract (nerves, synapse, decussation)

- Motor cortex => most fibers decussate at caudal medulla and descend contralaterally (lateral tract) **some fibers descend ipsi and decussate at level of spinal root - Synapse 1 at anterior horn - Leaves spinal cord and goes to NMJ

Multiple sclerosis

- Scanning speech - Intention tremor - Nystagmus "SIN"

Dural venous sinuses

- Sup. sagittal and straight sinus meet at the Confluence of the sinuses - Great Vein of Galen is inferior to Inferior Sagittal Sinus (not labeled) - All drain into IJV

Spinothalamic tract (nerves, synapse, decussation)

- Synapses in spinal cord at lower level - Decussates in ant. white commissure and ascends to VPL - Synapse in VPL and goes to sensory cortex

Amyotrophic lateral sclerosis

- UMN and LMN lesions - Fasciculations leading to atrophy - No sensory or oculomotor defects - 2/2 superoxide dysmutase mutation - Riluzole tx helps a little "riLOUzole for LOU gehrig's."

Corticospinal tract

- Voluntary movement - Head is medial

Occlusion of anterior spinal artery

DCLM is spared