Spinal Cord Syndromes

Front 1

spinal root exits

Back 1

C1-7 above C1-7 vertebrae; C8 between C7 and T1; T1-coccygeal below corresponding vertebrae; conus medullaris at L1 (spinal cord ends); dural sac and subarachnoid space end at S1

Front 2

dermatomes (by general area: 6)

Back 2

no C1; C2-4 neck, C5-T1 arms; T2-L1 trunk (T4 nipple, T10 umbilicus); L2-S2 legs; S2-S5 perineum

Front 3

lateral corticospinal tract (alternate name, function, lesion causes what and why)

Back 3

aka pyramidal pathway; controls voluntary movements of distal muscles (mainly flexors); inhibits muscle tone and DTRs (GABA) -> causes hyperflexia and spasicity if lesioned

Front 4

spinothalamic tract

Back 4

detects pain, temp, light touch; A-delta and C nerve fibers (naked terminals of small, unmyelinated fibers)

Front 5

corticospinal tract pathway and somatotopic

Back 5

UMN run from motor cortex through internal capsule then decussate at pyramids in lower medulla (90%) or continue ipsilaterally in anterior corticospinal tract (8% -> cross in anterior white commissure near termination level) or ipsilateral lateral corticospinal tract (2%), at level of termination synapse on anterior horn cells (LMN) or interneurons; somatotopic: arms medial and legs lateral (bows towards center)

Front 6

spinothalamic tract pathway and somatotopic

Back 6

1st axon (soma in dorsal root ganglion) enter via dorsal root and split into ascending/descending branches that run longitudinally in Lissauer's tract (posterolateral funiculus) for 1-2 segments, then synapse with dorsal horn cells, dorsal horn axons cross in anterior white commissure near level of entry (within 2 segments up or down) and then run vertically in contralaterally anterolateral funiculus and terminate in VPL, 3rd neuron in VPL projects to S1; arms medial and legs lateral (bows towards center)

Front 7

posterolateral funiculus

Back 7

Lissauer's tract (ipsilateral spinothalamic before crossing -> runs vertically 1-2 segments)

Front 8

anterolateral funiculus

Back 8

spinothalamic tract contralateral (after crossing near level of entry)

Front 9

dorsal column pathway and somatotopic

Back 9

1st axon (soma in DRG) enters via dorsal root and travels in dorsal column (fasciculus gracilis - leg; fasciculus cuneatus - arm); both fasciculi terminate in nuclei gracilis/cuneatus in lower medulla, 2nd axon decussates immediately and travels to VPL, 3rd neuron projects to S1; arms (FC) lateral and legs (FG) medial - bows away from center and towards dorsal horn

Front 10

sympathetic pathway

Back 10

arise in hypothalamus, descend ipsilaterally to synapse on T1-L2 spinal nerves

Front 11

bladder control

Back 11

reflex contraction occurs due to stretch receptors in bladder sending input to S2-4 LMN via dorsal roots; UMN inhibit this reflex; parasymp axons synapse on cell bodies in S2-4 ventral gray matter, causing detrusor muscle contraction

Front 12

atonic bladder

Back 12

due to lesion of sacral dorsal roots or cauda equina/conus medullaris (aka LMN) -> flaccid, loss of sensations, overflow incontinence (constant dribbling)

Front 13

spastic bladder

Back 13

due to lesion above conus and below pontomesencephalic micturition center b/c of UMN loss of inhibition on detrusor reflex; acutely caused acontractile bladder (urinary retention) and chronically causes reflex detrusor contraction and bladder emptying (incontinence)

Front 14

blood supply of spinal cord

Back 14

anterior 2/3 supplied by anterior spinal a. (arises from vertebrals) - supplies corticospinal (motor) and spinothalamic (pain/temp) tracts; posterior 1/3 supplied by posterior spinal arteries - supplies DC/ML tract (propioception, etc.); midthoracic region in watershed and thus vulnerable to hypotension

Front 15

complete cord transection symptoms

Back 15

loss of all motor function and sensation below lesion (pinprick may be a few levels below lesion); bowel and bladder dysfunction (spastic chronically) and other autonomic dysfunction (orthostatic hypotension, anhidrosis, impotence, etc.); acutely will see flaccid plegia and urinary/fecal retention while chronically will see spasticity and incontinence; if C1-3/4 will need ventilatory support and if below C7 retains ability to independently transfer (arms intact)

Front 16

Brown-Sequard syndrom

Back 16

hemisection of cord -> segmental LMN and sensory signs (flaccid at level), spastic below level (UMN), pain/temp contralateral a few levels below segment, propioception ipsilateral below segment

Front 17

syringomyelia

Back 17

syrinx = cavity filled with CSF; starts centrally and spreads centrifugally; first affects spinothalamic tract (capelike loss of pain/temp), followed by LMN bodies in anterior horn (flaccid at level)

Front 18

tabes dorsalis

Back 18

posterior column syndrome; impaired vibration and position sense leading to sensory ataxia (worse in dark -> positive Romberg sign); caused by untx syphylis (10-20 yrs) -> lancinating leg pains, absent leg reflexes, sphincter dysfunction, Argyll Robertson pupils, possible blindness

Front 19

Argyll Robertson pupils

Back 19

accomodate but don't react (small, miotic)

Front 20

sphylis

Back 20

causes tabes dorsalis -> posterior column syndrome (sensory ataxia)

Front 21

posterolateral column syndrome

Back 21

dsyfunction of both dorsal column and corticospinal tract (causing sensory ataxia and spasticity w/ hyperactive reflexes); causes by B12 deficiency -> myelin degeneration w/o inflammation

Front 22

B12 deficiency

Back 22

causes posterolateral column syndrome -> both dorsal column and cortiocspinal tract; peripheral neuropathy can also be present causes hyporeflexia (confusing - look for Babinksi sign to confirm)

Front 23

causes of anterior horn cell disease

Back 23

SMA (inherited: SMA and Kennedy's, acquired: PMA), infectious (polio, WNV, enterovirus 71, coxsackie, echoviruses

Front 24

SMA

Back 24

autosomal recessive LMN syndrome (attacks anterior horn cells) -> varies in severity from death occurring with 18 mo to adult onset w/o life shortening

Front 25

Kennedy's disease

Back 25

X-linked mutation in androgen receptor, causes (among other things) anterior horn cell disease

Front 26

ALS

Back 26

combined UMN + LMN in corticospinal tract

Front 27

anterior spinal artery occlusion

Back 27

blocks bilateral corticospinal tract and spinothalamic tract (spastic weakness below lesion, pain/temp loss a few levels below lesion), blocks anterior horn (flaccid weakness at level of lesion), impaired bowel/bladder control, preservation of DC/ML (proprioception, etc.); occurs most commonly in lower thoracic region (watershed) -> due to aortic dissection, atherosclerosis, hypotension

Front 28

intramedullary lesion causes (5)

Back 28

ependymoma, astrocytoma, glioblastoma, myelitis, abscess

Front 29

intradural extramedullary lesion causes (2)

Back 29

schwannoma, meningioma

Front 30

extradural lesion causes (5)

Back 30

disc disease, epidural metastasis, primary bone tumor, lymphoma, epidural abscess

Front 31

lumbar disc herniation symptoms

Back 31

below spinal cord -> LMN lesion of compressed nerve roots and dermatomal sensory loss (hyporeflexia), radicular pain, no bladder/bowel involvement

Front 32

cauda equina syndrome

Back 32

radicular lesion of multiple roots L4 and below -> severe radicular pain, flaccid weakness in legs with hyporeflexia. saddle region sensory disturbance (S3-5), bowel/blader dysfunction and impotence --- immediate surgical decompression necessary to save bladder fn

Front 33

causes of cauda equina syndrome

Back 33

lumbar disc herniation, spinal stenosis, tumor