Clinical Evaluation of Spinal Cord Flashcards
Myelopathy definition
Disorder resulting in spinal cord dysfunction
Nerve root definition
Combined sensory and motor rami of the spinal cord (e.g. L5)
Spinal tracts definition
Axons that travel in the spinal cord to relay information. (e.g. corticospinal tract).
Dermatome definition
Cutaneous area served by an individual sensory root.
Myotome definition
Muscles innervated by an individual motor root.
Radiculopathy definition
Sensory and/or motor dysfunction due to injury to a nerve root.
Intervertebral foramen definition
Opening formed by 2 adjacent vertebral bodies through which the nerve roots travel.
Paresthesia definition
An abnormal sensation, can include burning, pricking, tickling, or tingling
Dysesthesia definition
Impairment of sensation short of anesthesia
Hyperesthesia definition
Abnormal acuteness of sensitivity to touch, pain, or other sensory stimuli
Step-by-step approach to clinical evaluation of the spinal cord
- sx from hx and PE
- define UMN vs. LMN
- define tracts involved
- define anatomic sites involved
- differential dx
- workup
Spinothalamic tract: fxn and crossing point
- -Function: Sensory modalities of pain (pinprick) and temperature-cold/hot
- -Cross: 2-3 segments above root entry level in anterior spinal cord
Posterior/Dorsal Column: fxn and crossing point
- -Function: Sensory modalities of vibration, position, and 2-pt discrim
- -Cross: medulla (brain stem)
Corticospinal tract: fxn and crossing point
- -Function: Motor function
- -Cross: Lower medulla (brain stem)
Nerve root levels
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccyx
Conus medullaris level/definition
- located @~L1-L2 vertebrae where the spinal cord ends
- made up of S2-S5 spinal cord segments
Cauda equina definition
- formed by LS roots
- begins @ ~L1/L2 where the
Exit of nerve roots along spinal column
- -C1, 2, 3, 4, 5, 6, 7 roots exit above same numbered vertebra (e.g. C7 exits above C7).
- -C8 below C7 and all other roots exit below same numbered vertebra (e.g. T1 exits below T1).
Vertebral body vs. underlying cord segment @ cervical spine
- Upper cervical: vertebra # overlies same cord segment # (C2 bone, C2 cord)
- Lower cervical: vertebra # overlies cord segment # + 1 (C6 bone, C7 cord)
Vertebral body vs. underlying cord segment @ thoracic & lumbar spine
- Upper thoracic: vertebra # overlies cord segment # + 2 (T4 bone, T6 cord)
- Lower thoracic/lumbar: vertebra # overlies cord segment # +2- 3 (T 11bone, L1-2 cord)
- Lower edge of the L1 vertebral body overlies the cord tip (conus medullaris)
UMN injuries
- Corticospinal tract lesions in the spinal cord affect DTRs (deep tendon reflexes), strength, bulk, and tone in muscles AT or BELOW lesion on SAME SIDE of lesion.
- bulk: normal or disuse atrophy
- fasciculations: none
- tone: increased tone/spasticity
- DTR: hyperreflexia
- Plantar response: increased; extensor or babinski sign
DTRs of the arm and leg
- Arm: Biceps (C5, C6), Brachioradialis (C6, C7), Triceps (C6,C7), Fingers (C8).
- Leg: Quadriceps (L3, L4), Gastrocnemius (Achilles reflex, S1).
LMN injury characteristics
- bulk: decreased; significant atrophy
- fasciculations: present
- tone: decreased; flaccid
- DTRs: decreased or absent
- plantar response: decreased; flexor
Radiculopathy: sx, exam findings, localization
- “spinal root syndrome”
- Pain:
- quality is variable: “shooting,” “burning,” “tingling,” “numb.”
- often radiates into a dermatome or myotome.
- Exam: possible LMN signs (reduced or absent reflexes +/- weakness).
- Localization: determine which root the abnormal muscles(s) and dermatome(s) have in common.
Radiculopathy: exacerbating and relieving factors, common causes
- Exacerbation by Exam: Neck flexion/extension/rotation, shoulder movements, cough, etc.
- Relieving Factors: Rest, immobilization, graded therapy, NSAIDS +/- muscle relaxants.
- Common causes: Compression by degenerative joint disease (causing bony proliferation) or herniated disc near intervertebral foramen.
Lherrmitte’s sign
- Neck flexion ==> “electric shock” sensation down the back and/or into arms.
- Attributed to posterior column disease
- MS, disc, B12 deficiency, mass
Spinal cord pain syndromes
- Complete Cord Transection
- Central Lesions
- Posterior Column Syndrome
- Combined Anterior Horn Cell-Pyramidal Tract Syndrome
- Brown-Sequard (Hemi-Section)
- Posterolateral Column Syndrome
- Anterior Horn Cell Syndrome
- Anterior Spinal Artery Occlusion
- Pyramidal Tract Syndrome
- Myelpathy w/Radiculopathy
Complete Cord Transection: tracts & deficits
- Tracts: All ascending sensory & descending motor/autonomic tracts.
- Deficit: Sensory + motor levels below lesion; may also have root signs at site.
- Note: Spinal shock followed by UMN signs.
Central Lesions: tracts & deficits
- Tracts: Initially involve crossing ST
- E.g.s: Syringomyelia (fluid-filled cavity in cord), ependymomas, cord contusion.
- Deficit: PP/Temp loss at level of lesion, with sparing of position sensation.
- Note: Cape-like distribution if in C-spine.
Posterior Column Syndrome: tracts, e.g., deficits
- Tracts: PC
- E.g.s. Tabes dorsalis (form of neurosyphilis)
- Deficit: Bilateral loss of position & vibration sensation.
Combined Anterior Horn Cell-Pyramidal Tract Syndrome: tracts, e.g., deficits
- Tracts: CS and LMN cells in cord.
- E.g.s: Amyotrophic lateral sclerosis
- Deficit: Loss of bilateral strength.
- Note: Fasciculations, atrophy, increased or decreased DTR, normal sensation.
Brown-Sequard (hemi-section): tracts, e.g., deficits
- Tracts: Crossed ST + uncrossed PC + crossed CS
- E.g.: Compression by herniated discs, tumor, extramedullary abscess, etc.
- Deficit: Below lesion, loss of:
- CL PP/Temp
- IL Position
- IL strength.
Posterolateral Column Syndrome: tracts, e.g., deficits
- Tracts: PC + CS
- E.g.: B12 deficiency (aka subacute combined degeneration)
- Deficit: Bilateral loss of position & vibration, and strength.
Anterior Horn Cell Syndrome: tracts, e.g., deficits
- Tracts: None - lower motor neuron (cell).
- E.g.: Spinal muscular atrophy, polio virus
- Deficit: Bilateral loss of strength.
- Note: Fasciculations, decreased tone + decreased DTRs with sparing of all sensory tracts and bladder functions.
Anterior Spinal Artery Occlusion: tracts, e.g., deficits
- Tracts: ST + CS
- E.g.: Anterior spinal artery occlusion.
- Deficit: Bilateral loss of strength + PP/Temp, with sparing position sense.
Pyramidal Tract Syndrome: tracts, e.g., deficits
- Tracts: CS
- E.g.: Primary lateral sclerosis.
- Deficit: Bilateral UMN weakness with spastic gait, increased DTRs, but complete sparing of all sensory tracts and bladder function.
Myelopathy with Radicolpathy: tracts, e.g., deficits
- Tracts: Any or all 3 tracts (esp. CS)
- E.g.s: Cervical spinal stenosis, may be congenital or degenerative.
- Deficit: Bilateral UMN syndrome with spastic gait, increased DTRs + IL or CL root signs + possible bladder dysfunction.
Signs/sx of conus medullaris (S2-S5) syndrome
- -Late pain in thighs & buttocks
- -Pelvic floor muscle weakness
- -SYMMETRIC “saddle” anesthesia
- -EARLY bladder dysfunction
- -EARLY bowel & sexual dysfunction
Signs/sx of cauda equina (L1-L5 roots) syndrome
- -EARLY root pain radiating to legs
- -Leg weakness & decreased DTRs (LMN)
- -Patchy, asymmetric “saddle” numb.
- -Late bladder dysfunction
- -Late bowel & sexual dysfunction
Neuronal control of micturition
- most micturition related axons run in or along the LCST
- brain/brainstem send axons through spinal cord ==> preganglionic parasympathetic neurons @ S2, S3, S4
- pregang parasym axons ==> ventral roots of S2, S3, S4 ==> postganglionic parasympathetic neruons @ ganglia near bladder
- postgang parasym innervate detrussor
- pregang sympathetic neurons @ T11-L1 => contraction of internal urethral sphincter
- external sphincter = voluntary
- frontal cortex ==> descending inputs
- alpha motorneurons @ anterior horn from S3-S4
Spinal lesion impact on micturition
- @ sacral level:
- if sensory is intact ==> urgency w/out good detrussor contraction
- ==> ~LMN sx = weakness, atrophy, hyporeflexia
- above sacral level:
- bladder fxn is only affected w/bilateral lesion
- ~UMN sx = initially flaccid bladder ==> spastic bladder
Dematome @ nipple line, xyphoid, umbilicus
- T4 = nipple line
- T6 = xyphoid
- T10 = umbilicus
Sensory territory of C5, C6, C7
- C5 = @ level of clavicles; extends lateral and ventral along arms
- C6 = most lateral portion of arms
- C7 = middle of dorsal aspect of arms + middle palm and fingers 2,3
Sensory territories of L4, L5, S1
- L4/L5/S1 = foot
- most of ventral lower leg + lateral part of upper leg
