Lesion=dysfunction

Pain is not evidence of a nerve lesion, but a normal, healthy response spinothalamic pathway carries pain

Pain tells you that nerves are healthy and functioning normally

If you put pressure on a nerve, nerve can't function (i.e. you lose sensation in areas served by the nerve)

Nervous tissue function is conduction (sensory, motor, and combination of both)

If a nerve can still conduct, there is no lesion

If you stick your hand with a pin and don't feel pain, this is a neurological lesion

Things may look OK on x-ray but loss of function indicates a lesion (ex. whiplash)

Question: If there is a herniated disc at L5 but no apparent dysfunction, does this indicate a lesion?

Note: there is no static definition of function

Muscle spasm

A nerve is healthy as long as it's conducting

Facilitation

sensory nerve is facilitated (pain is felt)

numbness indicates a lesion

to complicate things, a patient can feel both pain and numbness at the same time

If both are occuring at same time=neurological lesion

Sensory

Motor

Reflex

EMG/NCV

If all these tests are normal, the nerve is healthy

1)Neurological lesion-decreased muscle tone (ex.-stroke)

2)Somatic lesion-muscles, tendons, ligaments, and joints involved

3)Visceral lesion-pancreas, other organs

4)psychological lesion

explains how a fixated segment sends noxious signals to nerves and nerves carry these signals elsewhere (i.e. to heart, etc.)

cannot have a somato-somatic reflex unless nerves are in good condition

-ex. tear a ligament-->get muscle spasm

touch cornea-->blink eye

viscero-somatic reflex

-breathe in dust and sneeze

asthma is not a neurological lesion

Inhibited nerve-what most chiros learned to call it

Dermatome-looking for loss of sensation

Myotome-looking for weakness

-all muscles in this group innervated by the same nerve root

-ex. if C5 is the problem you would expect the myotome to be weak, decreased

or absent DTR (DTR is a somato-somatic reflex), decreased sensation in the

dermatome (hypoesthesia)

EMG-Electromyogram

-run current through needles stuck in pt's arm (needles recordsignals from muscles)

deficits-get these with neurological lesion

-means prognosis is worse for the patient

PND-progressive neurological deficits

-refer patient to a specialist if you see this

-ex. treat pt. with chiropractic, the pt. "feels" better, but reflexes are worse (bad sign)

-so change therapy and reevaluate or refer to another Dr.

Pain pathways (spinothalamic)

Proprioceptive pathways (dorsal columns)

pain fiber goes through the DRG into the dorsal horn and decussates when enters the cord

peripheral nerve-from finger to dorsal horn

spinothalamic-from spine to thalamus

-thalamus perceives pain (deep, dull, achy pain)

thalamocortical-from thalamus to cortex

pain-in parietal lobe of the cortex

cortex-can discriminate (can detect sharp, localized pain)