Spinal Cord Disorders

Question 1

Nerve roots innervating deltoid and biceps?

Answer 1

C5, C6

Question 2

Nerve roots innervating triceps?

Answer 2

C7, C8

Question 3

Nerve roots innervating interossei and flexor digitorum (finger flexors)?

Answer 3

C8, T1

Question 4

Nerve roots innervating iliopsoas (hip flexors) and quads?

Answer 4

L2, L3, L4

Question 5

Nerve roots innervating tibialis anterior (foot dorsiflexor)?

Answer 5

L4, L5

Question 6

Nerve roots innervating gastrocnemius (foot plantar flexor)?

Answer 6

S2, S2

Question 7

What is radicular (root) pain?

Answer 7

Lightning, stabbing, shooting, or electrical pain in the dermatomal distribution of dorsal root

Question 8

What causes radicular pain?

Answer 8

Dorsal root inflammation

• Shingles (Herpes Zoster)
• Extramedullary: compression by a lesion outside the spinal cord (herniated disc, vertebral tumor) -> constant, dull, local pain
• Intramedullary: arises from inside the spinal cord -> more diffuse pain or none at all

Question 9

Rx acute radicular pain?

Answer 9

Analgesics, anti-inflammatory medications (including oral or epidural corticosteroids)
Nerve blocks
Surgical removal of causative lesions

Question 10

Rx chronic radicular pain?

Answer 10

Anticonvulsants (gabapentin, carbamazepine, etc.)

Antidepressants (duloxetine, amitriptyline, etc.)

Question 11

Describe the findings caused by a spinal cord lesion in the spinothalamic tract

Answer 11

Pain and temperature deficit in the contralateral body; note that the dermatomal level of loss only approximates the level of the lesion, since afferent fibers may ascend a few levels before decussating to the other side of the cord

Question 12

What causes a suspended pattern of pain/temperature deficit with sacral sparing? Explain.

Answer 12

Intramedullary lesion within the spinal cord itself
A lesion within or near the center of the spinal cord will disrupt the decussating fibers, and perhaps the medial portions of the tract. Since the sacral fibers are located most laterally, they may be spared.

Question 13

What causes pain/temperature deficit up to a level with sacral involvement?

Answer 13

Extramedullary lesion

Question 14

Describe the findings caused by a spinal cord lesion in the dorsal column tract. Explain.

Answer 14

Ipsilateral position sense/vibration deficits; the fibers do not decussate in the spinal cord (they decussate in the medulla)

Medial lesion will affect sacral level first (opposite of STT)

Question 15

Compare the pain experienced in intramedullary vs. extramedullary lesions.

Answer 15

Intra: diffuse or none
Extra: radicular

Question 16

Compare the sensory loss in intramedullary vs. extramedullary lesions.

Answer 16

Intra: suspended
Extra: to a level or sacral

Question 17

Compare the presence of sacral sparing in intramedullary vs. extramedullary lesions.

Answer 17

Intra: present
Extra: absent

Question 18

It should be noted that when a spinal cord lesion is localized to a certain level, this level refers to the cord itself and not the surrounding bony vertebral columns. Explain.

Answer 18

As humans grow and develop, the bony columns lengthen, but the cord does not; for example, a severe fracture and displacement of the T12 vertebral body would approximately affect the L3 level of the SC itself

Question 19

Presentation of a transection of transverse myelopathy?

Answer 19

UMN signs in limbs innervated by LMNs caudal or inferior to the level of the spinal cord lesions
LMN signs
Dermatomal level of sensory loss

Question 20

How does the presentation of a transection acutely differ from the expected presentation?

Answer 20

Spinal or neurogenic shock may be initially present -> weakness may be accompanied by decreased tone and muscle stretch reflexes, with UMN signs only gradually emerging weeks to even months later

Question 21

Causes of transverse myelopathy?

Answer 21

Extramedullary lesions such as tumors (especially vertebral mets), spinal stenosis (spinal cord compression from degeneration of the bony spinal column and herniated discs), extradural hemorrhage , or abscess
Severel apinal cord ischemia
Viral infections
Vaccine reactions
Autoimmune demyelination of the spinal cod (MS)

Question 22

What is a Brown-Sequard lesion and how does it present?

Answer 22

Hemisection

STT involvement -> contralateral deficit to pain and temperature
DC involvement -> ipsilateral deficit of vibration and position sense
CST/anterior horn cells -> ipsilateral weakness with UMN and LMN signs respectively

Question 23

Common causes of hemisection?

Answer 23

Trauma, extramedullary tumors, herniated discs with degenerative disease of the bony spine

Question 24

What is syringomyelia and how does it present?

Answer 24

Cavity within or near the center of the spinal cord caused by an intramedullary lesion and affecting gray matter primarily

Pain and temperature deficit (suspended sensory level with sacral sparing)
May expand slowly into the lateral STT -> sacral involvement and CST -> motor involvement

Posterior columns generally spared (preserved vibration and position sense)

Question 25

Causes of syringomyelia?

Answer 25

Intramedullary lesion -> tumors, impaired CSF flow, typically from a Chiari malformation
May be a late residual of severe spinal cord injury (hemorrhage resorbs, leaving a cavity)

Question 26

What supplies the anterior spinal artery? What does it supply?

Answer 26

Several radicular branches of the aorta

Anterior or ventral 2/3 of the spinal cord

Question 27

Causes of anterior spinal artery lesion?

Answer 27

Atherosclerotic disease of the aorta
Complication of surgery for an aortic aneurysm (most common cause)
Aortic dissection inciting thrombosis

Question 28

Presentation of anterior spinal artery occlusion?

Answer 28

Usually occurs in the lower thoracic or upper lumbar spinal cord -> involvement of the corticospinal tract that leads to paraplegia with UMN signs in the lower limbs, and a thoracic level of sensory loss, WITHOUT sacral sparing, to pain and temperature

Occurs suddenly, progresses over hours, back pain or radicular pain are common initial symptoms

Question 29

What classically causes posterolateral syndrome aka subacute combined degeneration? What are 2 other potential causes?

Answer 29

Vitamin B12 deficiency; copper deficiency, HIV

Question 30

Presentation of subacute combined degeneration?

Answer 30

Vibration and position sense are reduced or lost in the lower limbs -> unsteadiness and falling if the patient stands or walks in the dark or with eyes closed
CST involvement -> spastic paraparesis
Pain and temperature are NOT affected

Question 31

If LMN signs develop in the upper limbs and UMN signs in the lower limbs, what is suspected?

Answer 31

Cervical myelopathy -> C-spine MRI

Question 32

Compare presentation of cervical myelopathy to ALS.

Answer 32

ALS may present with only UMN or LMN lesion signs initially. In ALS, sensory pathways are not affected, bowel and bladder functions remain normal, and radicular pain is not present. Fasciculations are often prominent. Weakness may also begin focally, with impaired speech and swallowing, or asymmetrically, as in one shoulder.

Diagnosis becomes apparent when diffuse weakness with UMN and LMN signs progress without any better explanation or obvious cause

Question 33

Presentation of tabes dorsalis?

Answer 33

At first, lumbosacral dorsal roots become inflamed, producing severe radicular pains in the lower limbs

Dorsal columns degenerate secondarily, so impaired vibration and position sense i the lower limbs is noted

Eventually, most sensory fibers degenerate, causing loss of all sensation in the lower limbs, where reflexes are lost since the afferent reflex arcs are disrupted

Strength remains intact