Peripheral nerves Flashcards
What makes up a peripheral nerve exam
General inspection
Gait
Myotomes
Tone
Deep tendon reflexes
UMNL Vs LMNL
General inspection
Scars: may provide clues regarding previous spinal, axillary or upper limb surgery.
Wasting of muscles: suggestive of lower motor neuron lesions or disuse atrophy.
Tremor: there are several subtypes including resting tremor and intention tremor.
Fasciculations: small, local, involuntary muscle contraction and relaxation which may be visible under the skin. Associated with lower motor neuron pathology (e.g. amyotrophic lateral sclerosis).
Myoclonus: brief, involuntary, irregular twitching of a muscle or group of muscles. All individuals experience benign myoclonus on occasion (e.g. whilst falling asleep) however persistent widespread myoclonus is associated with several specific forms of epilepsy (e.g. juvenile myoclonic epilepsy).
Hypomimia: a reduced degree of facial expression associated with Parkinson’s disease.
Gait
- Gait and stance are reliant upon many factors: Vision, Sensation, Proprioception, Motor output.
- Unsteadiness on standing with the eyes open is common in cerebellar disorders – Cerebellar Ataxia
Cerebellar Ataxia
- Cerebellar dysfunction leads to a broad-based, unsteady (ataxic) gait, which usually makes tandem walking (walking heel to toe in a straight line) impossible
- Instability which only occurs, or is markedly worse, on eye closure is indicative of proprioceptive sensory loss, referred to as Sensory Ataxia
Abnormal gait examples
Bilateral upper motor neuron damage causes a scissor-like gait due to spasticity. (Spasticity – incr muscle tone & spasm)
Propulsive gait – a stooped, stiff posture with the head and neck bent forward
Scissors gait – legs flexed slightly at the hips and knees like crouching, with the knees and thighs hitting or crossing in a scissors-like movement
Spastic gait – a stiff, foot-dragging walk caused by a long muscle contraction on one side
Steppage gait – foot drop where the foot hangs with the toes pointing down, causing the toes to scrape the ground while walking, requiring someone to lift the leg higher than normal when walking
Waddling gait – a duck-like walk that may appear in childhood or later in life
Gait and co-ordination tests
For cerebullum ataxia/Co-ordination impairment. Common in MS
Rombergs sign/pronator drift – stand with feet togther and arms out in front for 30secs the repat with eyes closed. Or in supination, observe if patients pronate involuntaily. +Ve if Pt cannot remain balenced
Finger-nose test – Pt touches nose then practintioners finger, which is moving left to rght & forward/backwards. +Ve if Pt over shoots and misses – issues with depth perception. False posative may by an optic injury.
Heel/shin test
Dysdiadochokinesis – Pt places palm ontop of palm in supination, then pronation, then repated again and again.
Myotomes
A group of muscles which is innervated by single spinal nerve root
Ranked from 1 to 5. 1 being no visible contraction, 3 movement against gravity and 5 normal power.
First ask Pt to do the movement first to check they can do the movement against gravity, tells you there are already a three.
Myotomes (lower)
L2-S2
* L2 Hip flexion, knee bent Pt drives knee to chest then down into
* L3 kick the door (Knee extension)
* L4 Dorsiflex and invert foot, resist Pt pulling back to neutral
* L5 - Big toes – Pt tries to extend
* S1 Plantar flex
* S2 Heel to bum (Knee flexion)
Myotomes (upper)
C1-T1 myotomes for the upper body
* C1 Chin Tuck
* C2 Head back
* C3 - CSP SB
* C4 – Shoulder elevation
* C5 – Shoulder Abduction
* C6 – Elbow extension
* C7 - Elbow flexion
* C8 – Thumb extension
* T1 Finger Abduction, adduction.
Assessing tone – test for hypertonia
Tone – passive resistance to stretch, common in Parkinson’s and MS
Wrist – flex/extend
Elbow - flex/extend
Shoulder – abduction, adduction hips (‘roll’)
Knee - flexion
Tone is graded from 0 -4 (No response, Hypotonia, Normal response, Mild-moderate hypertonia, Severe hypertonia)
Stiffness – compliance to deformation
Deep tendon Reflexes
Biceps C5
Brachioradialis C6
Triceps C7
Patella L4
Achilles S1
Use Jendrassik manoeuvre – smile/grit their teeth, grip hands and try to pull apart, distracts them from the reflex
Loss of deep tendon reflex implication
Peripheral neuropathies secondary to diabetes, alcohol abuse, or inflammation.
Superficial reflexes
Umbilical T8-12 – Absent with corticospinal tract lesion.
Babinskis L5-S1 – Usually accompanied with Hyperreflexia, Clonus and increased tone. ADULTS: Normal – digital flexion Abnormal – digital fanning pattern. INFANTS – Normal digital fanning Abnormal – digital flexion.
UMNL
Anything that effects the brain (Stroke, infection, SOL, Parkinsons, MS etc) prior to the anterior horn of the spinal cord.
LMNL
– Anything that effects the neuron from anterior horn to the muscle it innervates (Peripheral nerve injury, bells palsy, Myasthenia Gravis, Guilain Barre syndrome)
