Peripheral Nerve examination Flashcards
What do you look for on general inspection?
Postural abnormalities and deformities? - look from the front and the side!!!
- May be due to weakness (stroke), contractures or spinal abnormalities (neurodegenerative conditions e.g. Parkinson’s disease (forward-flexed posture) or Friedriech’s ataxia (kyphoscoliosis)).
Muscle wasting?
- Suggestive of lower motor neuron lesions
Fasciculation/ Tremor?
- Fasciculations are irregular contractions of small areas of muscles ( ‘writhing of a worm’ under the skin) suggestive of lower motor neurone lesions
- Resting tremors (e.g. pill-rolling tremor in Parkinson’s disease) occur when the patient is sitting or lying comfortably, whereas intention tremors occur on movement and can signify a cerebellar disorder
Abnormal movements?
- tremor, chorea (jerky, dance-like, involuntary movements of limb or face - associated with Huntington’s and other non-neurological conditions e.g. thyrotoxicosis), myoclonus (brief, shock-like jerks in one or more muscle groups and usually rhythmical - associated with juvenile myoclonic epilepsy).
(Also inspect bed space for mobility aids)
How to examine tone of arms?
Check if the pt is in any pain
Ask them to let their arms go floppy and flex them for them at the elbow and the wrist and supinate and pronate the arm
Compare the two sides and look for:
Increase in tone - pyramidal deficits (clasp knife rigidity/clonus) or extrapyramidal (cog wheeling/ lead pipe rigidity)
Decrease in tone - LMN lesion
How to examine power of arms?
“I would just like to test the strength in your arms if that’s OK”- Repeat each step on both arms
First assess pronator drift - get them to hold arms out in front of them and assess for pronation, repeat with eyes closed
Get them to place knuckles together sticking elbows out - “put you arms up like a chicken” - “push up against me and down against me”
Hold arm at a bent angle as if shaking fist - “ put your arms up like a boxer’ - pull your arm towards you, and then push me away’
Get them to make a tight fist and cock their wrist up- “don’t let me push you down’ and do the same with extended fingers
Get them to spread fingers apart - “stop me pushing them together”
Get them to push their thumb against yours
Get them to make an OK sign and “stop me from pulling your finger and thumb apart”
How to examine coordination of arms?
Finger to nose test - Look for: Past-pointing (dysmetria) Intention tremor (compare to the resting tremor that can be seen in Parkinsonism)
Rapid alternating hand movements- get them to pronate and supinate one hand rapidly on top of the other- look for dysdiadochokinesia
What tendon reflexes should you examine in the arms and what spinal nerves do they test?
Biceps and Brachioradialis ( C5, 6)
Triceps (C7)
How do you test for sensation in the arms?
Light touch - Ask them to close eyes and touch sternum lightly with cotton wool- the pt should say ‘ yes’ when they feel it
Repeat in the upper limb dermatomes- “ can you feel it? Does it feel the same as on your chest?”
(C4 over shoulder, C5 over regimental badge, C6 over lateral aspect of lower arm, C7 over tip of middle finger, C8 over p. little finger, T1 on medial lower arm, T2 on medial upper arm)
Pain- repeat light touch procedure with a pin and ask the pt to say “sharp” or “blunt”
Joint position sense- isolate middle finger, get pt to close eyes and state if you are moving it up or down - splint finger so only distal phalanx moves
- compare left with right
- use more proximal joint if needed
Vibration sense - validation using sternum first, then on finger tip- ask pt to close eyes and state when vibration stops
How do you examine tone of the lower limb?
Ask if in any pain Let legs go floppy Roll legs on bed Flex and extend knee and ankle State that you are now going to look for clonus and it might be a little uncomfortable- forcibly extend quads (above knee) and rapidly dorsiflex ankle - if clonus is present you will see rapid sustained jerking - sign of increased tone
How do you examine power of the lower limb?
Hip flexion and extension
Nerve roots tested are: L2 (flexion) & S1 (extension)
Ask your patient to “keep knees straight and raise your leg…now stop me from pushing down…now press your leg against the bed…now stop me from lifting up”.
Hip abduction and adduction
Nerve roots tested are: L5 (abduction) & L3 (adduction)
Ask your patient to “move your leg out to the side…now stop me pushing your legs together…move your legs together again…now stop me from pulling your legs apart”
Knee flexion and extension
Nerve roots tested are: S2 (flexion) & L3 (extension)
Ask your patient to “bend at the knee…stop me straightening out your leg…push me away”
Ankle dorsiflexion and plantar flexion
Nerve roots tested are: L4 (dorsiflexion) & S1 (plantar flexion)
Ask your patient to “cock your feet up and don’t let me push them down…now push down and don’t let me push them back up”
How do you test coordination of the lower limb?
Heel-shin test
Ask the patient to slide the heel of one foot up and down the shin of the other leg (remember to demonstrate this).
Incoordination manifests as the foot veering off the intended path before reaching the ankle.
What tendon reflexes of the lower limb must you check?
Knee (L3/4), Ankle (S1), Plantar response (Babinski sign)
Plantar response
Nerve roots tested: L5/S1.
Method:
Warn the patient you are about to gently scratch the sole of their foot.
Using the blunt tip of a disposable orange stick, apply a firm stroke from the heel, up the lateral aspect of the sole, and across the metatarsophalangeal joints. Do NOT touch the big toe (causes an extensor response in a normal patient)
Watch the big toe for its initial movement: A normal (or negative plantar response) is plantar flexion of the big toe. An abnormal (or positive plantar response) is dorsiflexion of the big toe and may be indicative of an UMN lesion
How do you test sensation of the lower limb?
Light touch and pain same as in upper limb
L1- Inguinal region & very top of medial thigh
L2-Middle & lateral aspect of anterior thigh
L3-Medial aspect of knee
L4-Medial aspect of lower leg & ankle
L5-Dorsum & medial aspect of big toe
S1-Dorsum & lateral aspect of little toe
Proprioception: assess as you would for the upper limb but instead of testing the middle finger, start by testing the great toe in the same fashion and progressing to the next most proximal joint (i.e. ankle and so forth) should proprioception be absent.
Vibration: assess as you would for the upper limb but instead of placing the base of the tuning fork on the distal interphalangeal joint of the right thumb, place it on the metatarsophalangeal joint of the great toe.
How would you finish off your PNS exam?
Offer to assess gait and do a Rhomberg’s test
