Peripheral Nerve Exam - Lower Limb Flashcards
What is the main purpose of a neurological examination?
to localise where in the nervous system the problem is – is it UMN (brain, spinal cord) or LMN (nerve roots, peripheral nerve, NMJ or muscle)?
Define ataxia
Lack of muscle control or coordination of voluntary movements
Define fasciculation
A brief spontaneous contraction affecting a small number of muscle fibres, often causing a flicker of movement under the skin (i.e. muscle twitch).
Define choreiform
Involving involuntary movement that resembles chorea (jerky involuntary movements affecting especially the shoulders, hips and face)
Define athetosis
abnormal muscle contraction causes involuntary writing movements (affects some people with cerebral palsy)
Describe how athetosis and choreiform differ
Chorea is ongoing** jerky involuntary movements whereas athetosis is a **slow continuous, writing movement that prevents maintenance of stable posture.
UMN lesion vs LMN lesion → fasciculations?
UMN → no fasciculation
LMN → fasciculation of muscles
UMN lesion vs LMN lesion → wasting of muscle?
UMN → no significant wasting (may be disuse atrophy or contractures)
LMN → wasting of muscles
UMN lesion vs LMN lesion → tone?
UMN → increased tone (spasticity or rigidity)
LMN → decreased (hypotonia) or normal
UMN lesion vs LMN lesion → patterns of weakness?
UMN → Pyramidal patterns of weakness (extensors weaker than flexors in arms, vice versa in legs)
LMN → Different patterns of weakness depending on cause (e.g. proximal weakness in muscle disease, distal weakness in peripheral neuropathy)
Define a pyramidal pattern of weakness
Pyramidal weakness, that is, the weakness that preferentially spares the antigravity muscles, is considered an integral part of the upper motor neuron syndrome.
UMN lesion vs LMN lesion → reflexes
UMN → exaggerated or brisk (hyperreflexia)
LMN → reduced or absent (hyporeflexia/areflexia)
UMN lesion vs LMN lesion → plantar reflexes?
UMN → up going/extensor (Babinski positive)
LMN → normal (down going/flexor) or mute (no movement)
What 4 pieces of equipment is needed in a lower limb peripheral nerve exam?
- Tendon hammer
- Neurotip
- Cotton wool
- Tuning fork
Give the overall structure of a lower limb neuro exam
- Introduction
- General inspection: clinical signs (SWIFT), objects & equipment
- Gait
- Romberg’s sign
- Tone: leg roll, leg lift, ankle clonus
- Power: hip, knee, ankle, big toe
- Reflexes: knee jerk, ankle jerk, plantar
- Coordination: heel to shim, toe tapping
- Sensation: light touch, pinprick, vibration, proprioception
- Conclusion
The SWIFT acronym can be used when assessing the clinical signs during a lower limb neuro exam. What does this stand for?
S - Scars
W - Wasting of muscles
I - Involuntary movements
F - Fasciculations
T - Tremor
Would the presence of fasciculations be indicative of an UMN or LMN lesion?
LMN lesion e.g. amyotrophic lateral sclerosis
Give 2 types of tremors
Resting tremor
Intention tremor
Give some examples of involuntary movements that may be present
- Chorea
- Pseudo-athetosis
- Myoclonus
- Tardive dyskinesia
What is myoclonus?
Brief, involuntary, irregular twitching of a muscle or group of muscles
All individuals experience on occasion (e.g. whilst falling asleep) but persistent widespread myoclonus is associated with specific forms of epilepsy (e.g. juvenile myoclonic epilepsy)
What is persistent widespread myoclonus associated with?
specific forms of epilepsy (e.g. juvenile myoclonic epilepsy)
What is tardive dyskinesia? What can it occur 2ary to?
involuntary, repetitive body movements e.g. protrusion of tongue, smacking and grimacing which can develop 2ary to treatment with neuroleptic medications e.g. antipsychotics and antiemetics
Hypomimia may be present in certain neurological conditions. What is this? What condition is it associated with?
Reduced degree of facial expression associated with Parkinson’s disease
Ptosis and frontal balding are signs typically associated with which neuro disease?
Myotonic dystrophy
Ophthalmoplegia may be present in certain neuro conditions. What is this? Give some conditions where it might be present
weakness/paralysis of one or more extraocular muscles responsible for eye movement (e.g. multiple sclerosis, myasthenia gravis)
What screening question. should be asked before assessing the patient’s gait?
Are you able to walk unaided
When assessing the patient’s gait, what signs are you looking for?
- Stance
- Stability
- Arm swing
- Steps
- Turning
What may a broad-based, ataxic gait indicate?
A midline cerebellar pathology e.g. a lesion in multiple sclerosis or degeneration of the cerebellar vermis 2ary to chronic alcohol excess)
What may a staggering, slow and unsteady gait indicate?
Cerebellar pathology → in unilateral cerebellar disease, patients will veer towards the side of the lesion
How is arm swing affected in Parkinson’s disease?
Often absent or reduced (typically unilateral initially)
What type of steps may be seen in Parkinson’s?
Small, shuffling
High-stepping steps may indicate the presence of what?
Foot drop
What is the purpose of assessing the patient’s tandem (heel-to-toe) gait?
This exacerbates underlying unsteadiness, making it easier to identify more subtle ataxia.
What is the purpose of assessing the patient’s tandem (heel-to-toe) gait?
This exacerbates underlying unsteadiness, making it easier to identify more subtle ataxia.
What is the tandem (heel-to-toe) gait particularly sensitive at identifying?
Dysfunction of the cerebellar vermis (e.g. alcohol-induced cerebellar degeneration)
What is the purpose of Romberg’s test?
Test used to assess for loss of proprioceptive or vestibular function (sensory ataxia) but does NOT assess cerebellar function (i.e. used to quickly screen for non-cerebellar causes of balance issues).
What is a positive Romberg’s sign? What does this indicate?
Falling without correction
Indicates unsteadiness due to sensory ataxia i.e. deficit of proprioceptive or vestibular function, rather than cerebellar function.
What is proprioception
Proprioception is the body’s ability to sense its location, movements, and actions.
Give some causes of proprioceptive dysfunction
- Joint hypermobility (e.g. Ehlers-Danlos syndrome)
- B12 deficiency
- Parkinson’s disease, ageing (presbypropria)
Which vitamin deficiency can lead to a positive Romberg’s sign?
B12
What are some causes of vestibular dysfunction?
- Vestibular neuronitis
- Meniere’s disease
Is swaying with correction a positive Romberg’s result?
No
What is the typical cause of swaying with correction in a Romberg’s test?
often cerebellar disease (due to truncal ataxia)
How should the patient be positioned when assessing tone/
Examine patient sat on bed with their legs extended in a relaxed position in front of them.
What are the 3 parts of the ‘tone’ assessment?
- Leg roll
- Leg lift
- Ankle clonus
What are you assessing during the leg roll?
- Assessing tone in the muscles responsible for rotation of hip
- Observe foot movement to gauge if any increase/decrease in muscle tone
What are you assessing during the leg lift? How would increased tone present?
Normal tone: knee should rise whilst heel remains in contact with bed
Increased tone: heel will typically lift off bed
What is ankle clonus? Does clonus indicate UMN or LMN lesion? Give some conditions
Clonus is a series of involuntary rhythmic muscular contractions and relaxations that is associated with UMN lesions of the descending pathways (e.g. stroke, multiple sclerosis, cerebral palsy).
How would ankle clonus present? What is considered abnormal?
Clonus is felt as rhythmic beats of dorsiflexion and plantarflexion
If more than 5 beats of clonus are present, this would be classed as an abnormal finding
Spasticity and rigidity are both are features of increased tone seen in UMN lesions.
How does the location of the lesion differ between spasticity and rigidity?
Spasticity → Associated with pyramidal tract lesions (e.g. stroke)
Rigidity → Associated with extrapyramidal tract lesions (e.g. Parkinson’s disease)
Does Parkinson’s involve an extrapyramidal or pyramidal lesion?
Extrapyramidal tract lesion
Is spasticity or rigidity velocity dependent?
Spasticity is velocity dependent → i.e. faster you move limb, the worse it is
Rigidity is NOT velocity dependent → i.e. feels the same if you move limb slowly or rapidly
What is ‘clasp-knife’ spasticity?
Initial resistance (increased tone) followed by sudden reduction in resistance to movements
What are the 2 main subtypes of rigidity?
- Cog-wheel rigidity
- Lead-pipe rigidity
Cogwheel vs lead pipe rigidity?
Lead pipe rigidity is defined as a constant resistance to motion throughout the entire range of movement.
Cogwheel rigidity refers to resistance that stops and starts as the limb is moved through its range of motion.
What condition is cog wheel rigidity associated with?
Parkinson’s disease
What condition is lead pipe rigidity associated with?
- Detected in disorder of basal ganglia
- Associated with neuroleptic malignant syndrome (a potentially life-threatening reaction to antipsychotic drugs or major tranquilizers)
What 4 components are tested in ‘power’?
- Hip
- Knee
- Ankle
- Big toe
What 4 aspects are tested in ‘hip’ power?
- Flexion
- Extension
- Abduction
- Adduction
What myotome is being tested in hip flexion? Which nerve? Which muscle?
Myotome → L1 / L2
Nerve → Iliofemoral nerve
Muscle → Iliopsoas
What myotome is being tested in hip extension? Which nerve? Which muscle?
Myotome → L5/S1/S2
Nerve → inferior gluteal
Muscle → gluteus maximus
What myotome is being tested in hip abduction?
Myotome → L4/L5
What myotome is being tested in hip adduction?
L2/L3
What 2 aspects are tested in ‘knee’ power?
Extension & flexion
What myotome is being tested in knee flexion? Which nerve? Which muscle?
Myotome → S1
Nerve → Sciatic nerve
Muscle → Hamstrings
What myotome is being tested in knee extension? Which nerve? Which muscle?
Myotome → L3/L4
Nerve → Femoral nerve
Muscle → Quads
What 2 aspects are tested in ‘ankle’ power?
- Dorsiflexion
- Plantarflexion
What myotome is being tested in ankle dorsiflexion? Which nerve? Which muscle?
Myotome → L4/L5
Nerve → Deep peroneal nerve
Muscle → Tibialis anterior
What myotome is being tested in ankle plantarflexion? Which nerve? Which muscle?
Myotome → S1/S2
Nerve → Tibial nerve
Muscle → Gastrocnemius, soleus
What 2 aspects are tested in ‘big toe’ power?
- Flexion
- Extension
What myotome is being tested in big toe extension? Which nerve? Which muscle?
Myotome → L5
Nerve → Deep peroneal nerve
Muscle → Extensor hallucis longus
Is a pyramidal pattern seen in UMN or LMN lesions?
UMN
How does a pyramidal pattern of weakness affect the lower limb and upper limb extensors and flexors?
Disproportionately affects the lower limb flexors and upper limb extensors (i.e. lower limb flexors weaker than extensors in a neurological assessment)
What pattern of weakness does a LMN cause?
Cause a focal pattern of weakness – only the muscles directly innervated by the damaged neurons affected
What is the MRC muscle power assessment scale?
Uses a score of 0-5 to grade the power of a particular muscle group in relation to the movement of a single joint.
What 3 reflexes should be assessed?
Knee jerk
Ankle jerk
Plantar
What nerve roots does the knee jerk reflex test?
What is the normal response?
L3/L4
Normal response: Kicking motion of lower leg
What nerve roots does the ankle jerk reflex test?
What is the normal response?
S1
Normal → Contraction in gastrocnemius with associated plantarflexion of foot
What nerve roots does the plantar reflex test?
What is the normal response?
L5/S1
Normal → Flexion of big toe and flexion of other toes
Which piece of equipment is used to test the plantar reflex?
Neurotip
What is Babinski’s sign?
Extension of big toe and spread of other toes → UMN lesion
Why do UMN lesions (e.g. stroke, spinal cord injury) lead to hyperreflexia?
due to loss of inhibition from higher brain centres which normally exert a degree of suppression over LMN reflex arc
Why do LMN lesions (e.g. brachial plexus pathology, peripheral nerve injuries) lead to hyporeflexia?
due to loss of efferent and afferent branches of normal reflex arc
In cerebellar disease, how are reflexes described?
Pendular
What does pendular mean?
less brisk and slower in their rise and fall
Which pieces of equipment are used to assess sensation?
Light touch → cotton wool
Pin prick → neurotip
Where should you demonstrate normal sensation for the patient?
Over sternum
Dermatomes for sensation:
- L1: Inguinal region and very top of medial thigh
- L2: Middle and lateral aspect of anterior thigh
- L3: Medial aspect of knee
- L4: Medial aspect of lower leg and ankle
- L5: Dorsum and medial aspect of big toe
- S1: Dorsum and lateral aspect of little toe
Which type of sensation involves both the dorsal columns and spinothalamic tracts?
Light touch
Which type of sensation involves only the spinothalamic tracts?
Pin prick
If loss of sensation is noted peripherally, what should you then do?
Test for “stocking” distribution of sensory loss by moving distal to proximal.
If necessary, keep going all the way up the leg and trunk until an area of normal sensation is identified. This may reveal a “sensory level”, which is suggestive of a spinal lesion (e.g. if there is abnormal sensation up to the level of the umbilicus, this suggests a spinal lesion at around T10).
What does stocking distribution of sensory loss indicate?
Peripheral neuropathy
if there is abnormal sensation up to the level of the umbilicus, what spinal level is the lesion likely at?
around T10
What piece of equipment is used to assess vibration sensation?
128 Hz tuning fork
Where is the tuning fork placed to test vibration sensation?
Interphalangeal joint of big toe (both sides)
If vibration sensation is impaired at DIP of big toe, where should you assess next?
continue to sequentially assess more proximal joints (e.g. MTPJ big toe → ankle joint → knee joint) until patient is able to accurately identify vibration
What 2 aspects are involved in assessing ‘coordination’?
- Heel-to-shin test
- Toe tapping
Why should power be assessed before coordination?
Weakness (e.g. from UMN lesion) can produce apparent incoordination of movements.
What could dysmetria (i.e. incoordination) when performing the heel-to-shin test indicate?
Suggestive of ipsilateral cerebellar pathology