Neuro Exam 2

What is the shape of spinal cord gray matter?

Butterfly/H-shape with ventral and dorsal horns

Function of ventral horn

Contains motor nuclei whose axons exit via ventral nerve roots to innervate skeletal muscle

Which lamina primarily contains motor nuclei?

Lamina IX

Function of dorsal horn

Receives sensory input

What does spinal cord white matter contain?

Ascending (sensory) and descending (motor) tracts

What is the cervical enlargement?

C3-T1 region with enlarged ventral horns for brachial plexus and increased white matter

What is the lumbar enlargement?

L1-S2 region with enlarged ventral horns for lumbosacral plexus

What does the ALS (Anterolateral System) carry?

Pain and temperature sensation

Where does the ALS cross?

Near the level of entry into the spinal cord

ALS lesion causes what deficit?

Contralateral pain and temperature loss below the lesion

What does the DCML carry?

Vibration, proprioception, light touch, discriminative touch

Where does the DCML cross?

In the medulla

DCML lesion causes what deficit?

Contralateral loss after decussation; spinal cord lesions cause ipsilateral loss below lesion

What is the function of the LCST?

Descending motor control (UMN pathway)

LCST lesion causes what signs?

UMN signs below the lesion

Anterior horn cell lesion causes what signs?

LMN signs at the level of lesion

LMN signs

Flaccidity, atrophy, hyporeflexia

UMN signs

Spasticity, hyperreflexia, Babinski sign

What supplies the anterior 2/3 of the spinal cord?

Anterior spinal artery

What supplies the posterior 1/3 of the spinal cord?

Posterior spinal arteries

What supplements spinal cord blood supply?

Radicular arteries from the aorta

What is the artery of Adamkiewicz?

Great radicular artery supplying lumbar and sacral cord

Where does the artery of Adamkiewicz arise?

T9-T12

Most vulnerable spinal cord watershed zone

T4-T8

Spinal cord somatotopy arrangement

Sacral fibers lateral, cervical fibers medial

What is Transverse Cord Syndrome?

Entire cord affected at one level

Transverse Cord Syndrome motor findings

Bilateral UMN signs below lesion

Transverse Cord Syndrome sensory findings

Bilateral loss of pain/temp and vibration/proprioception below lesion

Transverse Cord Syndrome LMN findings

LMN signs at lesion level

What is Anterior Cord Syndrome?

Damage to anterior 2/3 of cord with dorsal column sparing

Anterior Cord Syndrome motor findings

Bilateral UMN signs below lesion

Anterior Cord Syndrome pain/temp findings

Bilateral loss below lesion

Anterior Cord Syndrome vibration/proprioception findings

Intact

Common causes of Anterior Cord Syndrome

Trauma, MS, anterior spinal artery infarct

What is Posterior Cord Syndrome?

Damage limited to dorsal columns

Posterior Cord Syndrome findings

Loss of vibration, proprioception, discriminative touch below lesion

Posterior Cord Syndrome preserved functions

Motor and pain/temperature

What is Central Cord Syndrome?

Medial cord injury affecting cervical fibers

Classic Central Cord Syndrome finding

UE affected more than LE

Common cause of Central Cord Syndrome

Hyperextension injury with cervical stenosis

What is Brown-Sequard Syndrome?

Hemisection of spinal cord

Brown-Sequard LCST deficit

Ipsilateral UMN weakness below lesion

Brown-Sequard DCML deficit

Ipsilateral loss of vibration/proprioception below lesion

Brown-Sequard ALS deficit

Ipsilateral loss at lesion level and contralateral loss below lesion

Brown-Sequard memory tip

Motor and fine touch = ipsilateral; pain/temp = contralateral below

Purpose of ISNCSCI/ASIA exam

Classifies SCI level, completeness, and impairment

How many key sensory points are tested?

28 bilaterally

Sensory modalities tested in ISNCSCI

Light touch and pinprick/sharp-dull discrimination

What is DAP?

Deep Anal Pressure

Sensory grade 0

Absent

Sensory grade 1

Impaired

Sensory grade 2

Normal

Sensory grade NT

Not testable

Sensory level definition

Most caudal intact dermatome for pinprick and light touch bilaterally

How many key muscles are tested in ISNCSCI?

10 bilaterally

Key myotomes tested

C5, C6, C7, C8, T1, L2, L3, L4, L5, S1

Motor grade 0

No contraction

Motor grade 1

Visible/palpable contraction, no movement

Motor grade 2

Full ROM gravity eliminated

Motor grade 3

Full ROM against gravity

Motor grade 4

Movement against some resistance

Motor grade 5

Normal strength

Motor level definition

Lowest key muscle ≥3 if muscle above is grade 5

Neurological Level of Injury (NLI)

Most caudal segment with intact sensory and motor function

Criteria for complete SCI

No VAC + all S4-5 sensory = 0 + no DAP

What is ZPP?

Zone of Partial Preservation in complete SCI

AIS A

Complete injury

AIS B

Sensory incomplete

AIS C

Motor incomplete; less than half of muscles below NLI are grade ≥3

AIS D

Motor incomplete; half or more muscles below NLI are grade ≥3

AIS E

Normal sensory and motor function

SCALP layers

Skin, Connective tissue, Aponeurosis, Loose areolar tissue, Pericranium

Meninges from deep to superficial

Pia, Arachnoid, Dura

What is pia mater?

Innermost meningeal layer adherent to brain

What is arachnoid mater?

Middle meningeal layer

Where is CSF located?

Subarachnoid space

What are the two layers of dura?

Periosteal and meningeal

What is the falx cerebri?

Meningeal dural fold separating cerebral hemispheres

What is the tentorium cerebelli?

Dural fold separating cerebrum from cerebellum

What passes through the tentorial notch?

Midbrain

Epidural space location

Between skull and dura

What vessel is in epidural space?

Middle meningeal artery

Subdural space location

Between dura and arachnoid

What vessels are in subdural space?

Bridging veins

Subarachnoid space location

Between arachnoid and pia

Contents of subarachnoid space

CSF and major cerebral arteries

CSF is produced by what structure?

Choroid plexus

CSF flow pathway

Lateral ventricles → Foramen of Monro → 3rd ventricle → Cerebral aqueduct → 4th ventricle → Foramen of Magendie → Subarachnoid space

Epidural hematoma location

Between skull and dura

Cause of epidural hematoma

Middle meningeal artery rupture from temporal bone fracture

Classic epidural hematoma presentation

Lucid interval

Untreated epidural hematoma complication

Herniation and death

Subdural hematoma location

Between dura and arachnoid

Cause of subdural hematoma

Rupture of bridging veins

Shape of subdural hematoma

Crescent-shaped

Who commonly develops chronic subdural hematoma?

Elderly patients

Symptoms of chronic subdural hematoma

Headache, cognitive impairment, unsteady gait

Acute subdural hematoma cause

High-impact injury

Prognosis of acute subdural hematoma

Worse than chronic

Subarachnoid hemorrhage location

Between arachnoid and pia