Asymmetry, Deformity Or Abnormal Posture (Dystonia). Often due to abnormal contraction of one group of muscles. Some common dystonias have their own descriptions:
Writer’s cramp – the muscles of the hand and forearm cramp as the patient tries to write. They may only manage a few words before they have to stop.
Wry neck –torticollis – there is painful contraction of SCM – which cases the face to point to one side (Rarely it can be bilateral). Other variaionts involving other muscles are also possible; retrocollis – head tilts backwards, antecollis – head tilts forwards.
Resting Tremor(Parkinsons) or intention tremor (cerebellar disorder)
Fasciculation (Anterior Deltoid Margin And 1st Dorsal Interosseous)
Pronator Drift (UMN weakness)
Psuedoathetosis (Proprioceptive loss) – involuntary slow ‘snake-like’ movements of the distal regions (fingers and toes).
Dysmetria – lack of co-ordination (Cerebellar lesion)
Myoclonus – brief jerks, that can move a limb. Usually restricted to one muscle groups, but can be more generalised. For example, in normal individuals, the ‘shock’ that many people experience just as they fall asleep is myoclonus.
Tics – borderline psychiatric/neuro in origin. They can be consciously suppressed. They tend to affect the face and upper body. Many normal individuals have tics, that are completely benign. The main manifestation is in Tourette’s syndrome.
Ask patient to relax
Test shoulder, elbow, wrist and supinator catch – isolate each joint in turn.
Hypotonic – often can be subtle and difficult to distinguish. Possible LMN lesion.
MRC scale of 0-5 (see below)
First, ask the patient to hold their arms out infront of them, supinated. This tests and major weakness. In cases of UMN, the arm will drift downwards,and will pronate.
When describing weakness, think in terms of:
Proximal versus distal
Unilateral versus bilateral
Flex carpi radialis & ulnaris
Median & Ulnar
Ext carpi radialis & ulnaris
Radial & posterior interosseous
Dorsal interossei & Abd digiti minimi
Abd pollicis brevis
If you suspect someone is just not trying very hard, this can mimic weakness. This may be because they are in pain. To differentiate this from true weakness, quickly release the resistance during the examination. In those who are using the full effort, there will be some ‘rebound’ against the now absent resistance – e.g. the limb will quickly fly past the point where the resistance was. In someone not putting in full effort, you won’t see this rebound.
Hold tendon hammer at the end, let it fall in a pendular movement.
If unable to elicit a reflex try with reinforcement – “clench your teeth”
Look at the muscle belly when testing a reflex
cerebellar function – omit if upper limbs are weak.
Finger-nose test (look for dysmetria and intention tremor)
Alternating hand test looking for dysdiadochokinesis
Test distally to proximally. Look for “glove” (peripheral neuropathy) or dermatomal loss (nerve root problem)
Light touch with fingers/cotton wool (tests spinothalamic pathway). Don’t stroke the skin, gently ‘dab’ it.
Get the patient to close their eyes and look for extinction
Test rapidly, running up the arms then work down the arms specifically testing dermatomes as per the diagram
If deficit detected, consider refining deficit by using wisp of cotton wool (dorsal columns) as well as pin prick and testing temperature sensation (spinothalamic pathway)
Proprioception dorsal columns)
Thank the patient
Make sure the patient is comfortable and clothed
Wash your hands
Put your findings together – is the lesion central or peripheral?
Dr Tom Leach currently works as a GP Registrar and an Emergency Department CMO in Australia. He is also a Clinical Associate Lecturer at the Australian National University. After graduating from his medical degree at the University of Manchester in 2011, Tom completed his Foundation Training at Bolton Royal Hospital, before moving to Australia in 2013. He started almostadoctor whilst a third year medical student in 2009.
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