Neuro Upper Limb Flashcards
What is the main purpose of a neuro exam
What is the most basic question related to this?
to localise where in the nervous system the problem 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?
How can you differentiate an upper motor sign from a lower motor sign in the upper limb neuro exam on inspection
UMN: No fasciculation or significant wasting (there may however be some disuse atrophy or contractures)
LMN: Wasting and fasciculation of muscles
Is pronator drift present in upper limb UMN damage?
may be present for UMN injury
There may be some drift/movement of the arm(s) if weak or deafferented, but not pronator drift in LMN injury
How does tone change in the upper limb after a UMN vs LMN injury
UMN: Increased (spasticity or rigidity)
LMN: Decreased (hypotonia) or normal
How does power change in the upper limb after a UMN vs LMN injury
UMN: Classically a “pyramidal” pattern of weakness (extensors weaker than flexors in arms, and vice versa in legs)
LMN: Different patterns of weakness, depending on the cause (e.g. classically a proximal weakness in muscle disease, a distal weakness in peripheral neuropathy)
How do reflexes change in the upper limb after a UMN vs LMN injury
UMN: Exaggerated or brisk (hyperreflexia)
LMN: Reduced or absent (hyporeflexia or areflexia)
What equipment do you need in the neuro exam (upper limb)
Tendon hammer
Neurotip
Cotton wool
Tuning fork (128Hz)
What are the main stages of the upper limb neuro exam
Gather equipment
Intro (WIPERQQ)
Inspection
Pronator Drift
Tone
Power (Shoulder, Elbow, Wrist, Hand/fingers)
Reflexes (Biceps, supinator, triceps)
Sensation (dermatomes, light touch sensation, pin-prick sensation, vibration sensation, proprioception)
Coordination
Further assessments
What clinical signs do you look for at the beginning of the upper limb neuro exam (11)
Scars: may provide clues regarding previous spinal, axillary or upper limb surgery.
Wasting of muscles
Tremor
Fasciculations
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
Tardive dyskinesia
Hypomimia: a reduced degree of facial expression associated with Parkinson’s disease.
Ptosis and frontal balding: typically associated with myotonic dystrophy.
Ophthalmoplegia
What are fasciculations
What are they associated with
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).
What is 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).
What is 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.
What is Ophthalmoplegia?
What can cause it?
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 objects should you look for in a neuro upper limb exam
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.
How do you assess pronator drift
- 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).
Why is assessing pronator drift useful
Checking for pronator drift is a useful way of assessing for mild upper limb weakness and spasticity:
On assessment, 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.
How do you assess tone in upper limb muscles (4)
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).
How does spasticity present
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.
Are spasticity and rigidity the same?
No
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.
How is spasticity different from rigidity
Spasticity is “velocity-dependent”
Rigidity is “velocity independent” meaning it feels the same if you move the limb rapidly or slowly.
What are the 2 key 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.
(Remember - Rigidity is “velocity independent” meaning it feels the same if you move the limb rapidly or slowly.)
Which myotome and muscles are assessed for shoulder abduction
Myotome assessed: C5 (axillary nerve)
Muscles assessed: deltoid (primary) and other shoulder abductors (Supraspinatus, Trapezius, and Serratus Anterior)
What muscles are involved in shoulder abduction
Supraspinatus, Deltoid, Trapezius, and Serratus Anterior.
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How do you assess shoulder abduction
- 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.”
Which myotomes and muscles are assessed in shoulder adduction
Myotomes assessed: C6/7 (thoracodorsal nerve)
Muscles assessed: teres major, latissimus dorsi and pectoralis major
Which myotomes and muscles are assessed in shoulder adduction
Myotomes assessed: C6/7 (thoracodorsal nerve)
Muscles assessed: teres major, latissimus dorsi and pectoralis major
How do you assess shoulder adduction
- 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.”
Which myotomes and muscles are assessed in elbow flexion
Myotomes assessed: C5/6 (musculocutaneous and radial nerve)
Muscles assessed: biceps brachii, coracobrachialis and brachialis