Anatomy

• Spinal cord ends as

conus medullaris at
level of first lumbar
vertebra

• lumbar and sacral

nerve roots exit below
this and form the
cauda equina

Neuroanatomy

• Corticospinal tracts
• Spinothalamic tracts
• Dorsal (posterior) columns

Corticospinal Tract

• Descending motor pathway
• Forms the pyramid of the medulla
• In the lower medulla, 90% of fibers

decussate and descend as the lateral

corticospinal tract

• Synapse on LMN in the spinal cord
• 10% that do not cross descend as the

ventral corticospinal tract

• Damage to this part cause ipsilateral

UMN findings

Spinothalmic Tract

• Ascending sensory tract from skin and

muscle via dorsal root ganglia to
cerebral cortex

• Temperature and pain sensation
• Damage to this part of the spinal cord

causes:

– Loss of pain and temperature sensation in

the contralateral side

– Loss begins 1-2 segments below the level of

the lesion

Dorsal (Posterior)

Columns

• Ascending neurons that do not synapse

until they reach the medulla at which
point they cross the midline to the
thalamus

• Transmits vibration and proprioceptive

information

• Damage will cause ipsilateral loss of

vibration and position sense at the level
of the lesion

Complete vs

Incomplete

• Incomplete:

– Sensory, motor or both functions are

partially present below the neurologic level

of injury

– Some degree of recovery

• Complete:

– Absence of sensory and motor function

below the level of injury

– Loss of function to lowest sacral segment
– Minimal chance of functional motor recovery

Light touch…

• Transmitted through both the

dorsal columns and the
spinothalamic tracts

• Lost entirely ONLY if both tracts are

damaged

Upper vs. Lower Motor

Neuron

•

Upper motor neuron lesion

–

Motor cortex internal capsule
brainstem

spinal cord

•

Lower motor neuron lesion

–

Anterior horn cell nerve root
plexus

peripheral nerve

Basic Features of

Spinal Cord Disease

•

UMN findings below the lesion

–

Hyperreflexia and Babinski’s

•

Sensory and motor involvement
that localizes to a spinal cord level

•

Bowel and Bladder dysfunction
common

•

Remember that the spinal cord ends
at about T12-L1

Motor Exam

•

Strength - helps to localize the lesion

–

Upper cervical

•

Quadriplegia with impaired respiration

–

Lower cervical

•

Proximal arm strength preserved

•

Hand weakness and leg weakness

–

Thoracic

•

Paraplegia

–

Can also see paraplegia with a midline lesion in
the brain

•

Tone

–

Increased distal to the lesion

Sensory Exam

•

Establish a sensory level

–

Dermatomes

•

Nipples: T4-5

•

Umbilicus: T8-9

•

Posterior columns

–

Vibration

–

Joint position sense (proprioception)

•

Spinothalamic tracts

–

Pain

–

Temperature

Autonomic

disturbances

•

Neurogenic bladder

–

Urgency, incontinence, retention

•

Bowel dysfunction

–

Constipation more frequent than
incontinence

•

With a high cord lesion, loss of
blood pressure control

•

Alteration in sweating

Total transsection

-

Injuries

-

Tumors

-

infection

Total transsection

Below the lesion: first stage

-

Loss of motor function

-

Loss of sensory

-

Areflexion

-

Decreased tension of muscles

Total transsection

Below the lesion: second stage

-

Normal reflexesincreased

-

Normal
tensionincreasedspasticity

Total transsection

Bladder:

1.

Areflexion

2.

Ischuria paradoxa

3.

Automatic or autonomic

Spinal Shock

• Loss of neurological function and

autonomic tone below level of
lesion

• Loss of all reflexes
• Resolves over 24-48h but may last

for days

Spinal Shock

• Symptoms:

• Flaccid paralysis
• Loss of sensation
• Bladder incontinence
• Bradycardia
• Hypotension
• Hypothermia

Hypotension

• Must determine cause:

– Spinal cord injury
– Blood loss
– Cardiac injury
– Combination of above

Neurogenic Shock

• Neurogenic Shock:

– Warm
– Peripherally vasodilated
– Bradycardic

• Bradycardia may be caused by

something other than neurogenic shock

• Cervical spine injury may cause

sympathetic denervation

Brown-Séquard

Syndrome

• Hemisection of the cord
• Ipsilateral loss of:

– Motor function
– Proprioception and vibration sense

• Contralateral loss of:

– Pain and temperature sensation

BSS

• Caused by:

– Penetrating injury
– Lateral cord compression from:

• Disk protrusion
• Hematomas
• Bone injury
• Tumours

• Prognosis: GOOD

Central Cord Syndrome

• Older patients
• Preexisting central

spondylosis

• Hyperextension injury
• Injury affects central cord>

peripheral cord

• Damage to corticospinal

and spinothalamic tracts

• Upper extremities>thoracic

>lower extremities>sacral

CCS

• Present with:

– Decreased strength
– Decreased pain and temperature

sensation

– Upper>lower extremities
– Spastic paraparesis/quadriparesis
– Maintain bladder and bowel control

• Prognosis: GOOD

– Although fine motor recovery of the

upper extremities is rare

signs

intramedulla

ry

extramedullary

Radicul

ar pain

unusual

common

Vertebr

al pain

unusual

common

Funicul

ar pain

common

Less common

Umn

Sign

+, late

+, early

Lmn

sign

+++, diffuse Unusual,

segmental

Paraest

hesia

progr

descending

ascending

sphinct

er

early

late

Trophic common

unusual

Conus medullaris lesion

Pelvic floor weakness, early sphincter dysfunction
Autonomous neurogenic bladder
Constipation, impaired ejeculation and errection
Symmetric saddle anaesthesia
Pain
Tethered spinal cord:
numbness feet
asymmetric muscle atrophy of calf and thigh,

UMN signs, bowel bladder dysfunction,foot

deformities, cutaneous manifestations of spinal

dysraphism

Cauda equina lesion



Compression lumbar sacral roots below

L3 vertebra



U/L early radicular pain, worse at night



Flaccid hypotonic areflexic paralysis

producing peripheral paraplegia



Asymmetrical sensory loss in saddle area



KJ variable, ankle ↓↓



Sphincter dysfunction similar to conus

lesion but late

Cauda Equina

Syndrome

• Peripheral nerve injury to lumbar, sacral

and coccygeal nerve roots

• Symptoms:

• Variable motor and sensory loss in lower

extremities

• Bowel and bladder dysfunction
• Saddle anaesthesia

• Prognosis: GOOD

Conus Medullaris vs.

Cauda Equina Lesion

Finding

Conus

CE

Pain

Uncommon Common

Reflexes

Increased

Decreased

Bowel/bladder

Common

Uncommon

Stretch signs

-Laseque
-Fajersztajn-Krzemicki
-Mackiewicz
-Neri
-Naffziger
-Bikeles

Vascular syndromes of

spinal cord



Anterior spinal artery syndrome:

Territory – anterior funiculi, anterior horn,

base of the dorsal horn, peri ependymal

area, antero medial aspect of lateral

funiculi

Lower thoracic sement and conus- vulnerable

Abrupt onset of radicular pain, girdle pain

Flaccid quadriplegia, paraplegia

Bowel bladder dysfunction

Thermo anaesthesia analgesia

Position vibration light touch preserved



Posterior spinal artery syndrome:

Uncommon
Loss of position , proprioception,

vibration

Loss of segmental reflexes
Pain , temperature – preserved
Motor function- preserved

spinal cord claudication