09 Spinal cord structure and fxn Flashcards
Conus medularis vertebral level?
L1/2
where to do lumbar puncture?
L4/5
structures at inferior end of spinal cord
- conus medularis
- cauda equina (lumbrosacral roots)
- filum terminale (pia mater) connects to coccygeal ligament
How many spinal nerves do you need to lose to experience total sensory loss of a dermatome?
3 adjacent spinal nerves, because of dermatome overlap
Which spinal nerve does not innervate a dermatome?
C1
White matter tracts and their fxns
-Fasciculus gracilis-legs
-Fasciculus cuneatus-arms
(fine touch, vibration, conscious proprioception, 2 point discrimination)
- Lateral corticospinal tract-motor
- Rubrospinal tract
-Post/Ant spinocerebellar tract
-Lat/Ant spinothalamic tract
(pain, crude touch, temperature)
Dorsal horn Rexed regions
Rexed I-VI: sensory
I: marginal zone-pain, temperature
II. substantia gelatinosa-interneurons
III-V: mehcanical, visceral, noxious stimuli
VI: cervical and lumbar enlargement
Gray matter Intermediate Zone Rexed region
- Dorsal part of VII
- Clarke’s nucleus- dorsal spinocerebellar tract
- Intermediolateral cell column: Sympathetic neurons T1-L2, PS in S2-4
Ventral horn Rexed regions
Ventral VII-IX: motor
-houses alpha and gamma motoneurons
Lesion of upper motor neuron vs lower motor neuron
UMN: spastic paralysis
LMN: flaccid paralysis
Rhizotomy
cut dorsal spinal root for anesthesia or tx for certain kinds of spasticity
Symptoms of Brown-Sequard syndrome, ipsilateral and contralateral sides
Ipsilateral:
- loss of fine touch, vibration, 2-point discrimination, conscious proprioception
- spastic paralysis
Contralateral:
-loss of pain, temp
Syringomyelia
cyst forms in central canal of spinal cord
-can damage nearby fibers
