Neuro Exam: Upper Limb Flashcards
What is the main purpose for the neurological examination
The main purpose of a neurological examination is to localise where in the nervous system the problem is. This can seem daunting, but with practice, it is relatively straightforward. The most basic localisation question you have to think about during the upper and lower limb examination is:
Is there an upper (i.e. brain or spinal cord) or lower (i.e. nerve roots, peripheral nerve, neuromuscular junction or muscle) motor neuron lesion?
What are the key signs of an upper motor neurone lesion
Inspection: No fasciculation or significant wasting (there may however be some disuse atrophy or contractures).
Pronator drift: May be present
Tone: Increased (spasticity or rigidity)
Power: Classically a “pyramidal” pattern of weakness (extensors weaker than flexors in arms, and vice versa in legs)
Reflexes: Exaggerated or brisk (hyperreflexia)
What are the key signs of a lower motor neurone lesion
Inspection:Wasting and fasciculation of muscles
Pronator drift; There may be some drift/movement of the arm(s) if weak or deafferented, but not pronator drift
Tone:Decreased (hypotonia) or normal
Power: Different patterns of weakness, depending on the cause (e.g. classically a proximal weakness in muscle disease, a distal weakness in peripheral neuropathy)
Reflexes: Reduced or absent (hyporeflexia or areflexia)
Describe the introduction to the exam
Wash your hands and don PPE if appropriate.
Introduce yourself to the patient including your name and role.
Confirm the patient’s name and date of birth.
Briefly explain what the examination will involve using patient-friendly language.
Gain consent to proceed with the examination.
Adequately expose the patient’s arms for the examination from the shoulders to the hands.
Position the patient appropriately (either sitting on the side of the examination couch or lying at 45°).
Ask the patient if they have any pain before proceeding with the clinical examination
What equipment do you need for the purposes of the exam
Tendon hammer
Neurotip
Cotton wool
Tuning fork (128Hz)
What should you look for upon general inspection
Neurofibromatosis is a genetic disorder that causes tumors to form on nerve tissue. These tumors can develop anywhere in your nervous system, including your brain, spinal cord and nerves. Neurofibromatosis is usually diagnosed in childhood or early adulthood.
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).
Pseudoathetosis: abnormal writhing movements (typically affecting the fingers) caused by a failure of proprioception.
Chorea: brief, semi-directed, irregular movements that are not repetitive or rhythmic but appear to flow from one muscle to the next. Patients with Huntington’s disease typically present with chorea.
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).
Tardive dyskinesia: involuntary, repetitive body movements which can include protrusion of the tongue, lip-smacking and grimacing. This condition can develop secondary to treatment with neuroleptic medications including antipsychotics and antiemetics.
Hypomimia: a reduced degree of facial expression associated with Parkinson’s disease.
Ptosis and frontal balding: typically associated with myotonic dystrophy.
Ophthalmoplegia: weakness or paralysis of one or more extraocular muscles responsible for eye movements. Ophthalmoplegia can be caused by a wide range of neurological disorders including multiple sclerosis and myasthenia gravis.
What medical paraphernalia are relevant in the neurological examination
Look for objects or equipment on or around the patient that may provide useful insights into their medical history and current clinical status:
Walking aids: the ability to walk can be impacted by a wide range of neurological pathology.
Prescriptions: prescribing charts or personal prescriptions can provide useful information about the patient’s recent medications
Describe assessment of pronator drift
Assessment
Checking for pronator drift is a useful way of assessing for mild upper limb weakness and spasticity:
- Ask the patient to hold their arms out in front of them with their palms facing upwards and observe for signs of pronation for 20-30 seconds.
- If no pronation occurs, ask the patient to close their eyes and observe once again for pronation (this typically accentuates the effect due to the reliance on proprioception alone).
Describe the interpretation of the pronator drift
If the forearm pronates, with or without downward movement, the patient is considered to have pronator drift on that side. The presence of pronator drift indicates a contralateral pyramidal tract lesion. Pronation occurs because, in the context of an UMN lesion, the supinator muscles of the forearm are typically weaker than the pronator muscles.
What is a mnemonic for remembering the order of steps in the exam
Tone Power Reflexes Coordination Sensation
To Postpone Reflexes Constitutes Stupidity
Describe assessment of tone
Assessment
Assess tone in the muscle groups of the shoulder, elbow and wrist on each arm, comparing each side as you go:
- Support the patient’s arm by holding their hand and elbow.
- Ask the patient to relax and allow you to fully control the movement of their arm.
- Move the muscle groups of the shoulder (circumduction), elbow (flexion/extension) and wrist (circumduction) through their full range of movements.
- Feel for abnormalities of tone as you assess each joint (e.g. spasticity, rigidity, cogwheeling, hypotonia).
What is the difference between muscle tone and muscle strength
Muscle tone is defined as a skeletal muscle’s inherent resistance to passive movement. It is particularly important to differentiate this from muscle strength, which is a muscle’s maximum voluntary resistance to movement.
What are spasticity and rigidity associated with
Spasticity is associated with pyramidal tract lesions (e.g. stroke) and rigidity is associated with extrapyramidal tract lesions (e.g. Parkinson’s disease). Spasticity and rigidity both involve increased tone, so it’s important to understand how to differentiate them clinically.
What are the key features of spasticity
Spasticity is “velocity-dependent”, meaning the faster you move the limb, the worse it is. There is typically increased tone in the initial part of the movement which then suddenly reduces past a certain point (known as “clasp knife spasticity”). Spasticity is also typically accompanied by weakness (particularly in the extremities)
Spasticity may be present more upon extension than flexion- explains differences in posture in patients with hemiparesis
What are the key features of rigidity
Rigidity is “velocity independent” meaning it feels the same if you move the limb rapidly or slowly. There are two main sub-types of rigidity:
Cogwheel rigidity involves a tremor superimposed on the hypertonia, resulting in intermittent increases in tone during movement of the limb. This subtype of rigidity is associated with Parkinson’s disease.
Lead pipe rigidity involves uniformly increased tone throughout the movement of the muscle. This subtype of rigidity is typically associated with neuroleptic malignant syndrome.
Summarise how power is assessed
Assess the power of the patient’s upper limbs by working through the sequence of assessments below.
You must stabilise and isolate the relevant joint for each assessment to ensure you can accurately measure and compare muscle strength. As a result, you should only assess one side at a time.
At each stage in the assessment, you should compare like for like.
Use the MRC muscle power assessment scale for scoring muscle strength (details below).
You need to communicate clear instructions to the patient during each stage of the assessment. Demonstrating each position you want the patient to assume can aid understanding.
Must use same muscles as patient- i.e we use shoulder when testing shoulder strength
Describe assessment of the power of shoulder abduction
Shoulder ABduction
Myotome assessed: C5 (axillary nerve)
Muscles assessed: deltoid (primary) and other shoulder abductors
Instructions:
- Ask the patient to flex their elbows and ABduct their shoulders to 90°: “Bend your elbows and bring your arms out to the sides like a chicken.”
- Apply downward resistance on the lateral side of the upper arm whilst asking the patient to maintain their arm’s position: “Don’t let me push your shoulder down.”
Describe the assessment of power of shoulder adduction
Shoulder ADduction
Myotomes assessed: C6/7 (thoracodorsal nerve)
Muscles assessed: teres major, latissimus dorsi and pectoralis major
Instructions:
- Ask the patient to ADduct their shoulders to 45° bringing their elbows closer to their body: “Now bring your elbows a little closer to your sides.”
- Apply upward resistance on the medial side of the upper arm whilst asking the patient to maintain their arm’s position: “Don’t let me pull your arms away from your sides.”
Describe the assessment of the power of elbow flexion
Elbow flexion
Myotomes assessed: C5/6 (musculocutaneous and radial nerve)
Muscles assessed: biceps brachii, coracobrachialis and brachialis
Instructions:
- Ask the patient to flex their elbow: “Put your hands up like a boxer.”
- Apply resistance by pulling the forearm whilst stabilising the shoulder joint: “Don’t let me pull your arm away from you.”
Describe the assessment of power of elbow extension
Myotome assessed: C7 (radial nerve)
Muscles assessed: triceps brachii
Instructions: With the patient’s elbows still in the flexed position, apply resistance by pushing the forearm towards the patient whilst stabilising the shoulder joint: “Don’t let me push your arm towards you.”
