Neurologic lesion localization: Spinal neuropathies (Proceedings)

Aug 01, 2008

Spinal cord localization principles

It is helpful to develop an ordered approach to this problem. The following stages in the diagnostic approach should include:

1. Identifying the problem

2. Localizing the lesion

3. Assessing the severity or extent of the lesion

4. Acquiring a diagnosis

5. Determining the prognosis

Identifying the problem


1. Age/Breed

2. Previous history of illness; recent or previous trauma.

3. Course of the clinical signs –

Onset – very obvious or vague?

What were the initial signs? Any asymmetry?

Acute vs. progressive vs. static

Has condition stabilized, improved, worsened?

Has problem occurred before?

Clinical Examination:

It is important to do a thorough physical exam so that other diseases which may mimic neurologic conditions are not overlooked. Especially orthopedic disorders

Localization of the lesion

Determine the locomotor status first; this will help one evaluate which limbs are involved and assess for asymmetry, strength, and ataxia.

Assessment of proprioception

1. Knuckling response

2. Reflex stepping

3. Wheelbarrowing

Myotatic reflexes
4. Lateral hopping

Muscle atrophy –

1. LMN – severe, within 7-10 days

2. UMN – mild, takes weeks to occur

Other reflexes that may be evaluated –

1. Cutaneous trunci reflex –

Afferent arm – segmental sensory nerves

Efferent arm – C8-T1 – lateral thoracic nerve

2. Withdrawal reflexes –

Front limb – C5-T1 cord segments

Hind limb – L6-S1 cord segments

3. Anal reflex – S1-S3 cord segments

4. Crossed extensor reflex – this is manifested as a very rapid and extreme flexion of the stimulated limb after a noxious stimulus, with simultaneous extreme rapid extension of the opposite limb.

Bladder function

1. S1-S3 cord segments supply LMN and motor control to the bladder wall and urethral sphincters.

2. UMN vs. LMN bladder

a. UMN – 1. bladder may be full and distended

b. high resistance to manual compression

c. urine stream continues for a brief period after manual compression is stopped

d. after several days post-cord injury, the bladder will become hyperreflexic and hold less urine during the storage phase, but still retains more urine than a normal bladder after voiding.

e. LMN – 1. bladder full and distended

f. flaccid, no tone

g. dribbling of urine

h. bladder easy to express and urine stream ceases as soon as compression is stopped.