Upper Limb Neurological OSCE Examination

Contents

1. Introduction
2. General Inspection
3. Tone
4. Pronator Drift
5. Power
6. Reflexes
7. Coordination
8. Sensation
9. Completing the Examination
10. Quiz

Introduction

Wash your hands and don personal protective equipment if appropriate.

Introduce yourself to the patient and ensure to mention your grade e.g. 3rd year medical student/junior doctor/consultant.

Confirm the patient’s details taking 3 points of identification usually; full name, date of birth and NHS/hospital number.

Obtain consent for the examination, ensuring to explain what the examination will entail. A good explanation is something like “I’d like to examine the nerves and muscles of your arms, which will involve me looking at your arms, moving them, testing how strong they are, tapping a few tendons and checking your sensation – is that alright?”

Position the patient sitting on the edge of the bed or in a chair, where you have access to both arms.

Expose both upper limbs fully, including the shoulders, so that you can compare the two sides and inspect for muscle wasting.

Ask the patient if they are in any pain anywhere before you begin, as much of the examination involves moving the limbs.

General Inspection

Begin with a brief inspection of the patient and the bedside. Look for clues to a neurological diagnosis such as walking aids, a wheelchair, splints, wrist supports, or aids for daily living that hint at chronic disability.

Observe the patient’s posture and any abnormal movements at rest. A resting tremor that is worse at rest and improves with movement suggests Parkinson’s disease, whereas an action or intention tremor that worsens on reaching for a target points towards a cerebellar problem.

Inspect the arms and hands carefully for:

• Muscle wasting – loss of muscle bulk suggests a lower motor neurone lesion or disuse. Focal wasting of the small muscles of the hand (the ‘guttering’ between the metacarpals) is a classic sign of a T1 root or ulnar/median nerve problem.
• Fasciculations – fine, irregular twitches visible under the skin. These are caused by spontaneous discharge of a denervated motor unit and are a hallmark of lower motor neurone disease, most importantly motor neurone disease (amyotrophic lateral sclerosis).
• Tremor or other involuntary movements such as chorea, myoclonus or dystonia.
• Pseudoathetosis – slow, writhing finger movements seen when the patient holds the hands outstretched with the eyes closed. Rather than a movement disorder, this reflects a loss of proprioception (the brain cannot tell where the fingers are without vision) and points to a dorsal column or sensory nerve problem.
• Scars – over the wrist (carpal tunnel decompression), elbow (ulnar nerve transposition) or neck/spine (previous decompression surgery).
• Skin changes and abnormal posturing – a flexed, adducted upper limb may indicate a previous stroke with spasticity.

It is good practice to ask the patient to hold their hands out and briefly assess for symmetry before moving on. If you suspect a fine tremor that is hard to see, rest a sheet of paper across the dorsum of the outstretched hands – the paper amplifies and makes visible an otherwise subtle postural tremor, such as that of essential tremor or thyrotoxicosis. Remember to look at the palmar and dorsal surfaces of both hands, as wasting and scars can be missed on a single view.

Tone

Tone is the resting resistance of a muscle to passive stretch. To assess it, ask the patient to relax and let you take the full weight of the arm. Support the limb and move the shoulder, elbow and wrist through their full range of movement at varying speeds, comparing the two sides.

There are three abnormal patterns to recognise:

• Spasticity – a velocity-dependent increase in tone, meaning the faster you move the limb the greater the resistance. There may be a sudden ‘give’ partway through the movement (the ‘clasp-knife’ phenomenon). Spasticity affects the flexors preferentially in the upper limb and indicates an upper motor neurone lesion such as a stroke or spinal cord injury.
• Rigidity – an increase in tone that is constant throughout the range of movement and independent of speed. ‘Lead-pipe’ rigidity is smooth throughout, whereas ‘cogwheel’ rigidity has a ratchet-like quality caused by a superimposed tremor. Rigidity is a feature of extrapyramidal disease, classically Parkinson’s disease.
• Hypotonia – reduced tone, where the limb feels floppy. This suggests a lower motor neurone lesion or, in the acute phase, a cerebellar lesion.

It can help to distract the patient by asking them to count or name the days of the week while you move the limb, as voluntary ‘help’ from the patient can mask the true resting tone.

Pronator Drift

Pronator drift is a sensitive test for a subtle upper motor neurone lesion. Ask the patient to hold both arms out straight in front of them with the palms facing upwards (supinated) and the eyes closed. Observe for around 20–30 seconds.

In a positive test, the affected arm slowly pronates (the palm turns to face downwards) and drifts downwards. This occurs because, in a pyramidal lesion, the supinator muscles are weaker than the opposing pronator muscles, so the unopposed pronators win out when conscious control is removed by closing the eyes. A positive result indicates a contralateral corticospinal (pyramidal) tract lesion.

If the arm instead drifts upwards, or the hand makes searching, writhing movements, this suggests a loss of proprioception (sensory ataxia) rather than weakness. An arm that overshoots when you tap it down and then springs back is part of the cerebellar ‘rebound’ phenomenon, discussed under coordination.

Power

Power should be tested at each major joint, comparing left with right and testing the patient against your own resistance. Always fix the joint proximal to the one you are testing and ask the patient to resist you maximally. Power is graded using the Medical Research Council (MRC) scale:

• 0 – no muscle contraction
• 1 – a flicker of contraction
• 2 – movement possible only with gravity eliminated
• 3 – movement against gravity but not against resistance
• 4 – movement against resistance but reduced
• 5 – normal power

Each movement corresponds to a myotome (the muscles supplied by a single nerve root) and to one or more peripheral nerves. Knowing both allows you to distinguish a root lesion from a peripheral nerve lesion. Assess the following:

• Shoulder abduction (deltoid) – C5, axillary nerve. “Push your elbows up like wings and don’t let me push them down.”
• Shoulder adduction – C6/C7.
• Elbow flexion (biceps) – C5/C6, musculocutaneous nerve.
• Elbow extension (triceps) – C7, radial nerve.
• Wrist extension – C6, radial nerve. Weakness here with a preserved triceps suggests a radial nerve palsy (‘wrist drop’).
• Wrist flexion – C7.
• Finger extension – C7, posterior interosseous (radial) nerve.
• Finger abduction – T1, ulnar nerve. Weakness suggests an ulnar nerve or T1 lesion.
• Thumb abduction – T1, median nerve. Weakness with thenar wasting suggests carpal tunnel syndrome.

The pattern of weakness is more informative than the absolute grade. A pyramidal pattern of weakness – in which the upper limb extensors are weaker than the flexors – points to an upper motor neurone lesion. Weakness confined to a single myotome suggests a radiculopathy (nerve root compression), whereas weakness in the territory of one peripheral nerve suggests a mononeuropathy. Symmetrical proximal weakness suggests a myopathy, while distal weakness with sensory loss suggests a peripheral neuropathy.

Reflexes

Deep tendon reflexes test a monosynaptic reflex arc: tapping the tendon stretches the muscle spindle, which fires an afferent signal to the spinal cord, producing a reflex contraction. The reflex is modulated by descending upper motor neurone pathways, so the result tells you about both the local reflex arc and the pathways above it.

Ensure the patient is fully relaxed and the limb is in a neutral, slightly flexed position. Strike the tendon with a tendon hammer, letting the weight of the hammer do the work. The three upper limb reflexes are:

• Biceps reflex – C5/C6. Place your thumb over the biceps tendon in the antecubital fossa and strike your thumb.
• Supinator (brachioradialis) reflex – C5/C6. Strike over the brachioradialis tendon, a few centimetres proximal to the wrist on the radial side.
• Triceps reflex – C7. Support the arm and strike the triceps tendon just above the elbow.

Reflexes are conventionally graded on a scale from 0 to 4+: 0 absent, 1+ present only with reinforcement, 2+ normal, 3+ brisk, and 4+ brisk with clonus. Always compare the same reflex on both sides, as asymmetry is often more meaningful than the absolute grade.

Interpret the response as follows:

• Absent or reduced reflexes (hyporeflexia) indicate a lower motor neurone lesion – a problem with the reflex arc itself, such as a radiculopathy, peripheral neuropathy or anterior horn cell disease.
• Brisk, exaggerated reflexes (hyperreflexia) indicate an upper motor neurone lesion, because loss of descending inhibition leaves the reflex arc disinhibited.

If a reflex appears absent, ask the patient to perform a reinforcement manoeuvre – for the upper limb, clenching the teeth (the Jendrassik manoeuvre uses the legs) – just before you strike the tendon, as this can bring out a diminished reflex.

You can also look for Hoffmann’s sign, an upper limb equivalent of an upgoing plantar. Support the patient’s middle finger and quickly flick the nail downwards so the fingertip flexes and then springs back. A positive sign is reflex flexion of the thumb and index finger. It reflects loss of descending inhibition and supports an upper motor neurone lesion, classically cervical myelopathy, although it can be present in some normal individuals so should be interpreted alongside the rest of the examination.

Coordination

Coordination tests primarily assess the cerebellum, which fine-tunes movement. The cerebellum exerts ipsilateral control, so a cerebellar lesion produces signs on the same side of the body as the lesion.

• Finger-to-nose test – ask the patient to touch their nose and then your fingertip repeatedly, with your finger held at arm’s length. An intention tremor (worsening as the finger approaches the target) and past-pointing (dysmetria), where the patient overshoots, indicate a cerebellar lesion. Position your finger so the patient has to fully extend their arm to reach it, as this exaggerates dysmetria.
• Dysdiadochokinesia – ask the patient to rapidly tap the palm and then the back of one hand alternately onto the other palm. The inability to perform these rapid alternating movements smoothly is called dysdiadochokinesia and is a sign of ipsilateral cerebellar disease.
• Rebound phenomenon – ask the patient to hold their arms outstretched, then briefly push one arm down and release it. Normally the limb returns to its starting position with minimal overshoot. An absent or exaggerated rebound, where the limb swings wildly past the starting point, reflects a failure of the cerebellum to coordinate the antagonist muscles and indicates cerebellar dysfunction.

The classic mnemonic for the constellation of cerebellar signs is DANISH: Dysdiadochokinesia, Ataxia, Nystagmus, Intention tremor, Slurred (scanning) speech and Hypotonia.

Sensation

Sensory testing maps the patient’s deficits onto the dermatomes (areas of skin supplied by a single nerve root) and peripheral nerve territories, and assesses the different sensory pathways within the spinal cord. Different modalities travel in different tracts, so testing each one helps localise the lesion:

• Fine touch, vibration and proprioception travel in the dorsal columns.
• Pain (pin-prick) and temperature travel in the spinothalamic tracts, which cross the midline at the level of entry into the cord.

Always start by demonstrating the stimulus on a neutral area such as the sternum so the patient knows what to expect, then test with their eyes closed, comparing left and right at equivalent points as you work down each dermatome.

• Light touch – dab the skin gently with a wisp of cotton wool (do not stroke).
• Pin-prick – use a disposable neurological pin to test the spinothalamic pathway.
• Vibration – place a vibrating 128 Hz tuning fork on a bony prominence, starting distally at a finger interphalangeal joint and moving proximally if sensation is impaired. Loss of vibration sense is an early sign of peripheral neuropathy and of dorsal column disease.
• Proprioception (joint position sense) – hold the sides of the patient’s distal interphalangeal joint and move it up or down, asking them to identify the direction with their eyes closed.

The upper limb dermatomes worth knowing are:

• C5 – the lateral upper arm over the deltoid (the ‘regimental badge’ area).
• C6 – the thumb and radial forearm.
• C7 – the middle finger.
• C8 – the little finger.
• T1 – the medial forearm at the elbow.

The pattern of sensory loss is diagnostic. A dermatomal pattern suggests a radiculopathy; loss in a single peripheral nerve territory suggests a mononeuropathy (for example, loss over the thumb, index and middle fingers in carpal tunnel syndrome); and a symmetrical ‘glove’ distribution suggests a peripheral neuropathy, such as in diabetes mellitus.

Image - A dermatome map showing the areas of skin supplied by each spinal nerve root. In the upper limb, sensory loss following the C5–T1 dermatomes points towards a nerve root problem (radiculopathy)

Public domain source by Ralf Stephan [Public domain]

Completing the Examination

Thank the patient and ensure they are comfortable and re-dressed, then wash your hands.

Summarise your findings and, importantly, state whether the picture fits an upper motor neurone pattern (increased tone, brisk reflexes, pyramidal weakness), a lower motor neurone pattern (wasting, fasciculations, reduced tone, reduced reflexes) or a cerebellar/sensory picture.

To complete the examination, suggest:

• Assessment of the patient’s gait, a lower limb neurological examination and examination of the cranial nerves to complete the neurological assessment.
• Assessment of higher functions and a more detailed examination of the cerebellum if cerebellar signs are present.
• Bedside tests including a blood glucose and urine dip.
• Relevant investigations such as nerve conduction studies and electromyography (EMG), blood tests (including HbA1c, vitamin B12 and inflammatory markers), and imaging such as an MRI of the brain or cervical spine depending on the suspected level of the lesion.

Quiz

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