see also: [[Neurovascular assessment]], [[Trauma - C-spine exam]] #Neuro > [!key points] > - The OSCE upper limb exam is different from a med school short case where the exam is "neuro" or "MSK." the context of emergency medicine may require either ; for example, consider a trauma examination of an upper limb injury or C-spine injury > - The “upper limb neuro” exam for a spinal injury is a bit different than the [[Neurovascular assessment|peripheral nerve exam]] insofar as a lesion at the spinal cord or nerve root level will affect upper limb functioning differently than a lesion of the peripheral nerve that comes from that level. For example, a C7 spinal lesion may affect radial, median, and ulnar nerve exam, whereas a more distal radial nerve lesion will have no effect on other “C7”- associated nerves Pragmatic structured neurological exam – upper limbs: - Exam for power in UL: Shoulder Abd (C5)/Add (C6-7), Elbow Flex (C5/6)/Ext (C7), wrist flex( C6/7)/ext (C7/8), finger flex/grip (C7/C8), finger ext (C8), finger abd (T1) - Examine sensation upper limb: Tests all dermatomes – lat shoulder (C5)/ lateral forearm or thumb (C6)/ middle finger (C7)/ little finger or medial hand (C8)/ medial forearm/arm (T1) - log roll if trauma - reflexes and proprioceptive testing | condition | findings | | ------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Parkinson's | - motor signs: forward-flexed posture, speech difficulties, resting tremor, cogwheel rigidity, bradykinesia, mask-like facial expression | | cerebellar lesion | [[vertigo\|nystagmus]], slurred speech, hypotonia, hyporeflexia, intention tremor, dysmetria, dysdiadochokinesis, ataxia | | ulnar nerve lesion | - wasting, [[Weakness]], numbness, tingling 5th finger and medial half of fourth finger<br>- abduction, adduction fingers <br>- curling up of 4th and 5th fingers ('ulnar claw') would be a severe finding | | median nerve lesion | - sensation: 1st and 2nd distal finger radial side, thenar eminence<br>- motor: opposition, flexion of interphalangeal thumb<br>→ anterior interosseous nerve no sensory component; test making OK sign | | radial nerve lesion | - sensation - dorsum of hand 1st web space<br>- motor - dorsiflex wrist, extend fingers | | radiculopathy | | | hemiplegia | | | myopathy | | ## upper limb nerve distribution myotomes | Movement | Nerve root | Muscle | Nerve | | ------------------ | ---------- | ------------------------------------------------- | --------------------------------------- | | shoulder ABduction | C5 | deltoid and supraspinatus | axillary nerve | | shoulder ADduction | C6/7/8 | latissimus and pec major | thoracodorsal | | elbow flexion | c5/6 | - biceps<br>- brachialis | musculocutaneous | | elbow extension | C7, 8 | triceps | radial nerve | | wrist flexion | C6/7 | - flexor carpi ulnaris<br>- flexor carpi radialis | - ulnar nerve<br>- median nerve | | wrist extension | C7/8 | extensor carpi radialis | radial nerve | | finger flexion | C6/7 | FDS and FDP | median & ulnar n | | finger extension | C7 | extensor digitorum | posterior<br>interosseous n<br>(radial) | | finger ABduction | T1 | dorsal interossei | ulnar | | thumb ABduction | T1 | abductor pollicis brevis | median | ![[Pasted image 20250316174738.png]] ![[Pasted image 20250316174700.png]] ## Dermatomes See also: [[Dermatomes]] C3 - supraclavicular fossa C4 - top of AC joint C5 - lateral side of antecubital fossa C6 - thumb (and variable lateral forearm) C7 - middle finger C8 - little finger T1 - medial (ulnar) side of antecubital fossa T2 - apex of axilla T4 - fourth IC space (nipple line) T10 - tenth IC space (umbilicus) ![[Pasted image 20241226134133.png|upper limb and trunk dermatomes]] ![[Pasted image 20241226134254.png]] ## arm drift 3 causes: 1. upper motor neurone (pyramidal) weakness) - eg due to stroke - drift of affect limbs due to muscle weakness and tend to be in downward direction. drifting starts distally with fingers and spreads proximally. may be slow pronation of the wrist and flexion of the fingers and elbow 2. cerebellar disease - drift is usually upwards. also includes slow pronation of wrist and elbow 3. loss of proprioception - drift (pseudoathetosis) is really a searching movement and usually only affects the fingers. loss of joint position sense and can be in any direction # Special situations ## Stroke # example qs - [RMH 2025 - radial nerve lesion](x-devonthink-item://B4E10AE0-C08A-46D7-974B-98F41FD70F20) - [ACEM 2016 st 10](x-devonthink-item://636661DB-689A-4DC1-99CA-A739C3037CF6)