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Upper Limb Examination

Upper Limb Neurological Examination

 

Firstly prepare yourself and the patient for the examination. An often used mnemonic for this sequence is WIPER: wash your hands, introduce yourself, permission, expose the patient, re-position the patient. The arms should be fully exposed including the shoulders, neck and upper back.

 

Inspection

Things to look for include:

  • Posture of the upper limbs: examples include flexed elbow and hyperpronated forearm (indicating pyramidal weakness); clawing of the fingers or hands (ulnar nerve palsy, T1 lesion, non-neurogenic causes e.g. Volkmann’s contracture).
  • Wasting: a sign of lower motor neurone lesions but also present in long standing upper motor neurone disease due to disuse atrophy. Is the wasting generalised or focal? If focal; is it the thenar eminence only (median nerve palsy e.g. Fig 1), hypothenar and first dorsal interosseus with clawing of the medial two fingers(ulnar nerve palsy e.g. Fig 2) or generalised hand wasting (T1 lesion)?

Fig 1: Left median nerve palsyFig 2: Right ulnar nerve palsy

  • Fasciculations: a sign of lower motor neurone lesions. This is involuntary twitching of muscle fibres due to spontaneous depolarisation of lower motor neurones causing contractions.
  • Scars: posterior midline neck scars for surgical decompression of symptomatic cervical spondylosis, traumatic scars from injury to the arm or axilla, ulnar nerve transposition scars around the elbow, carpal tunnel decompression scars at the wrist, breast surgery scars (potential injury to intercostobrachial nerve, long thoracic nerve or thoracodorsal nerve).
  • Abnormal movement: tremors, choreoathetosis, dystonia.

 

Finally, a very useful manoeuvre to begin with is to ask the patient to reach forward with their outstretched hands with their palms facing upwards. Ask the patient to close their eyes and briefly observe the fingers to look for writhing movements (pseudoathetosis) caused by severe proprioceptive disease. Also observe for pronator drift. This is positive if the arm starts to fall with the forearm drifting into pronation. This is a sign of pyramidal weakness. Then you can ask the patient to keep their arms in place whilst you gently tap each arm downwards. An exaggerated, pendular swinging of the arm around the original position may suggest cerebellar disease.

 

Assess Tone:

Before moving the arms, always ask if the patient is in pain or discomfort. Tone is assessed by passively moving the elbows through extension and flexion, moving the forearm through pronation and supination, moving the wrist through flexion, extension and circumduction.

You must decide if there is hypertonia (increased tone) or hypotonia (reduced tone) or normal tone. There are several types of hypertonia and understanding the differences between them will allow you to properly examine for them:

  1. Spasticity: this is velocity dependent and often called “clasp knife spasticity” and is a sign of pyramidal disease. Practically, it is elicited by comparing slow extension with quick extension of the elbow and slow supination with fast supination of the forearm. A “catch” during the quick movement indicates spasticity.
  2. Rigidity: this is not velocity dependent and there is increased tone throughout the range of movement; it is sometimes called lead pipe rigidity. This is a sign of extrapyramidal disease. There is sometimes an associated tremor which can be elicited by distraction techniques (e.g. flapping the contralateral arm or asking the patient to count backwards). Cogwheeling is rigidity plus tremor and is best felt at the wrist.
  3. Paratonia: hypertonia with an involuntary variable resistance during passive movement. Resistance increases with movement speed, but is not limited to a certain direction. It may be seen in dementia.

Increased tone usually suggests an upper motor neurone lesion; hypotonia suggests a lower motor neurone lesion or cerebellar lesion. Patients with acute stroke may sometimes have reduced tone but will later develop spasticity. Shoulder tone can rarely be attributed to neurological disease and its assessment is of limited use.

 

Power:

Muscle power is graded using the MRC scale, in which different degrees of power are denoted a number:

0. No movement

1. Flicker of muscle contraction

2. Movement of muscle with gravity eliminated

3. Movement of muscle against gravity

4. Movement of muscle against some resistance

5. Normal power

 

The customary sequence of examination is to test proximal to distal but depending on clinical context, the examination of individual muscles may also be required. The muscle belly or tendon should also be palpated during contraction. A common sequence of movements which are tested, along with muscle name, root, and peripheral nerve is shown in table 1:

Table 1: Movements of the upper limb



There are a few common pitfalls in technique students (and doctors!) fall into during the power examination:

1)      Resisting movement of the muscle too early. For example, whilst testing shoulder abduction examiners often begin resisting the movement before the patient is able to abduct their shoulders to 90 degrees. This makes it difficult to know if there is 4/5 power or only 2/5 power. The correct technique would be to let the patient perform the movement against gravity, then resist. If the patient cannot move the muscle against gravity, then remove its effect by asking the patient to perform the movement along the bed.

2)      Not isolating the muscle. This occurs frequently during elbow movements where the patient is asked to push the examiner away and uses her whole body weight with shoulder flexion to add power. Isolate each muscle by stabilising the relevant joint e.g. elbow during flexion and extension, wrist during wrist extension.

3)      Elbow flexion is performed by two main muscles: biceps and brachioradialis. Putting the forearm in full supination, elbow flexion tests biceps. Putting the forearm in the neutral position, midway between supination and pronation, elbow flexion tests brachioradialis. This is important to understand as biceps is supplied by the musculocutaneous nerve, whereas brachioradialis is supplied by the radial nerve.

4)      Thumb abduction is controlled by two different nerves but is often used as a test of median nerve motor function. Thumb abduction moves the thumb perpendicular to the plane of the palm. Patients often find it difficult to accurately perform this move. One tip is to ask the patient to flatten their hand on their lap, palm upwards. The examiner places his finger a thumbs length above the middle of the patients palm and simply asks the patient to touch his finger with their thumb. Once the patient does this, ask the patient to keep their thumb still. Attempt to adduct the thumb and palpate the belly of abductor pollicis brevis, located in the thenar eminence. Palpation of this muscle belly is important because thumb abduction is also controlled by abductor pollicis longus which is supplied by the radial nerve. Therefore using thumb abduction for median nerve motor function may be confounded by poor technique. 

Once power is examined and weakness is elicited you should consider which pattern weakness it falls into. Common patterns include:

1)      Proximal weakness or distal or generalised weakness?

2)      Weakness in a nerve distribution?

3)      Weakness in a myotome distribution?

4)      Is there fatigueability? (This suggests neuromuscular disease e.g. myasthenia gravis and can be tested by eliciting if there is increased weakness after repetitive muscle movement).

 

Coordination:

Coordination is looking for evidence of cerebellar lesions. The two main tests include finger-nose testing and dysdiadochokinesia.

1)      Finger-nose testing is performed by asking the patient to touch the tip of their nose and then the tip of your finger alternately. Make sure the patient has to fully use her outstretched hand to reach your finger. This will exaggerate intention tremor which is seen as an increasing amplitude tremor the closer the patient gets to the target. If present there is often dysmetria; misjudging the distance of your finger and therefore missing it. If the patient is clearly dysmetric, ask them to touch their chin instead, this will prevent them from injuring their eye.

2)      Dysdiadochokinesia is the inability to perform rapidly alternate moves. Ask the patient to supinate and pronate the forearm whilst tapping the palmar or dorsal aspect of their hand onto the contralateral palm. 

Deep tendon reflexes

The main reflexes tested in the upper limb are the biceps, supinator and triceps. Here are a few points on technique for those finding eliciting reflexes difficult:

  1. Get the patient to completely relax. Ask the patient to let you take the complete weight of their arm.
  2. Tendon hammer technique: grasp the tendon hammer from the end and use the weight of the hammer to provide the force. As you strike the tendon, inspect the muscle belly to look for contraction. Always test reflexes in pairs to compare.
  3. If you cannot elicit the reflex use reinforcement: usually after two attempts if you are unable to elicit the reflex, you should use reinforcement techniques. This is called Jendrassik’s manoeuvre.  For the upper limb, ask the patient to clench their teeth on the count of three, and strike the tendon at the same time. Reflexes are often denoted by a variable number of  “+” symbols, referred to as “plusses”.
      • “-“  = absent reflexes even with reinforcement
      • “+” = reflexes present with reinforcement
      • “++” = normal reflexes
      • “+++” = hypereflexia without clonus
      • “++++” = hypereflexia with clonus
    1. For the biceps reflex: flex the elbow to approximately 130 degrees, rest the arm and forearm onto the patient’s chest. Palpate the biceps tendon, place a finger onto it and strike your finger. Inspect for biceps contraction as well as palpating for a contraction under your finger. The biceps reflex tests C5,6 root and the musculocutaneous nerve.
    2. For the supinator reflex: this is actually testing brachioradialis and is best tested by striking a finger placed on the radial side of the forearm with it in the neutral position. Inspect for brachioradialis contraction in the lateral antecubital fossa. This tests C5,6 root and the radial nerve. 
    3. For the triceps reflex: bring the patients arm across the chest and strike the bare tendon just proximal to the olecranon. Observe for triceps contraction. This tests C7,8 root and the radial nerve.

    Hyperreflexia may indicate an upper motor neurone lesion; absent reflexes may indicate a lower motor lesion.

     

    Sensation:

    Two modalities of sensation are tested representing different spinal cord tracts. Proprioception and light touch is predominantly carried by the dorsal column whereas pain and temperature is carried by the spinothalamic tract.

    Testing proprioception

    Proprioception is the ability to sense joint position. This is important to coordinate movement, as well as to prevent joint damage. To test proprioception, grasp the distal phalanx of the index finger by the sides and isolate the distal interphalangeal joint. Demonstrate to the patient extension is denoted as “up” and flexion is “down”. Ask the patient to close their eyes and move the distal phalanx a few millimetres and ask the patient which way you are moving it. If the patient is unable to correctly identify the direction of movement, there is proprioceptive pathology. To identify how proximally the patient is affected, move either to the metacarpophalangeal joint or wrist and continue testing proprioception. Keep moving proximally to the elbow and then shoulder until the patient has normal joint proprioception. Remember to test both sides.

    Testing light touch and pain

    Use a wisp of cotton wool and a sharp point, often found on the end of neurotips, for pain sensation. Touch the patient’s sternum and explain this is the reference point the patient should mentally compare limb sensation with. Ask the patient to rest his arms in the anatomical position, close their eyes and then proceed to test the areas supplied by the different dermatomes in the upper limb:

    1. C5 – mid point of the lateral arm
    2. C6 – tip of the thumb
    3. C7 -  tip of the middle finger
    4. C8 – ulnar border of the little finger
    5. T1 – mid point of the medial arm

    If a peripheral nerve problem is suspected, individual nerves can be tested by eliciting sensation in the following areas:

    1. Radial nerve – dorsal hand, webspace between thumb and first finger
    2. Median nerve – radial border of the first finger
    3. Ulnar nerve – ulnar border of the little finger
    4. Musculocutaneous nerve – mid point of the lateral forearm
    5. Axillary nerve – “regimental area” found around the insertion of the deltoid muscle

    It is important to ask the patient if the sensation is the same as the sternum each time. If there are bilateral changes, ask how they compare to each other. Note that only asking if sensation is the same on both sides can miss bilaterally reduced sensation.

    Testing temperature:

    This is not often done but in principle it would be tested in the same manner as light touch and pain but with objects of different temperature e.g. cold side of a tuning fork.

     

    Additional examination points for suspected median nerve pathology

    Patients often appear as short cases for PACES cases and indeed in clinical practice with a history suggestive of median nerve neuropathy. This most commonly manifests as carpal tunnel syndrome – a compressive median nerve neuropathy within the carpal tunnel of the wrist. Symptoms are numbness and tingling in the thumb, index, middle finger and lateral half of the ring finger. This is often exacerbated at night, and can be relieved by shaking.

    When examining the median nerve, both motor and sensory function should be tested. Specific tests for identifying potential locations of nerve compression should also be done.

    Testing the motor function of the median nerve

    Thenar eminence wasting is highly suggestive of median nerve neuropathy. Thumb abduction is often used as a motor screening movement for median nerve disease. The median nerve supplies most of the flexor muscles in the forearm and the 'LOAF' muscles of the thenar eminence:

    1. Lateral 2 lumbricals
    2. Opponens pollicis
    3. Abductor pollicis brevis
    4. Flexor pollicis brevis

    Testing the sensory function of the median nerve

    As suggested above, this is tested on the radial border of the index finger. The median nerve however supplies the entire lateral palm from the wrist, to the tips of the first, second and half if the ring finger including the thumb. On the dorsum, only the tips of the index, middle and ring fingers to about the distal interphalangeal joint is supplied by the median nerve. Carpal tunnel syndrome does NOT usually affect the palm as the palmar branch of the median nerve supplying this area branches proximal to the carpal tunnel and does not run within it.

    Examining for the location of compression

    Carpal tunnel syndrome is caused by compression within this space. A number of clinical tests are described to try to reproduce these symptoms:

    1. Durkan’s test – direct pressure onto the flexor retinaculum, the roof of the carpal tunnel
    2. Tinel’s test – tapping the flexor retinaculum
    3. Phalen’s test – asking the patient to hyperflex the wrists, or reverse Phalen’s where the patient is asked to extend the wrists.

    Other anatomical regions apart from the wrist where the median nerve can be damaged include:

    1. Around the humerus e.g. secondary to supracondylar fracture therefore examine for cubitus varus (the so called “gunsling deformity”).
    2. In the cubital fossa: the median nerve can get compressed inbetween the heads of pronator teres and can mimic carpal tunnel syndrome; sometimes even needlessly putting patients through carpal tunnel decompression surgery! Test for this by asking the patient to resist supination. A positive test is reproduction of symptoms.
    3. In the forearm: the median nerve gives off a branch called the anterior interosseous nerve (AIN) which supplies part of flexor digitorum profundus, flexor pollicis longus and pronator quadratus. A simple way to test the AIN is to ask the patient to perform the “ok” sign. The patient should be able to flex the distal interphalangeal joint of the index and interphalangeal joint of the thumb to correctly shape the “ok” sign. Alternatively ask the patient to make a closed fist and bury their fingers into their hand. AIN palsy will result in the thumb, index and middle finger being still visible (fig 3).

    Fig 3: Right AIN palsy showing inability to flex distal phalanges of index finger and thumb

    Additional examination points for suspected ulnar nerve palsy

    The ulnar nerve supplies all of the intrinsic muscles of the hands except those in the thenar eminence. It also provides branches in the forearm to flexor carpi ulnaris and the medial two flexor digitorum profundi. The most common location for ulnar damage is the elbow where it winds around the medial epicondyle of the humerus and is prone to damage. Damage to the ulnar nerve can lead to a claw hand. This is where there is extension of the metacarpophalangeal joints (MCPJ) of the ring and little fingers, with flexion of their interphalangeal joints (IPJ). The clawed posture is due to denervation of the medial two lumbricals (whose action is to flex the fingers at the MCPJ and extend at the IPJs) and medial two flexor digitorum pronfundus muscles (whose action is to flex the ring and little fingers at the distal IPJs). The ulnar paradox is the description of increased deformity the more distal the lesion. This is because distal lesions preserve flexor digitorum profundus innervation which acts to flex the fingers more and cause more of a deformity.

    For motor testing, wasting of the hypothenar eminence and the intrinsic muscles of the hand is highly suggestive of ulnar neuropathy. Palpating the belly of the first dorsal interosseous muscle on index finger abduction is also a good area to check for intrinsic muscle wasting. An often used test is eliciting Froment’s sign (fig 4). This is where the examiner places a piece of paper between the patient’s thumb and index finger, and asks them to stop it being pulled out of their hand. Adductor pollicis is supplied by the ulnar nerve. Patients with ulnar nerve palsy will flex the interphalangeal joint of the thumb to keep the paper from slipping; this is supplied by the median nerve. This is a positive Froment’s sign. For testing sensation, the ulnar border of the little finger is used.

    Fig 4: Positive left Froment's sign

    Apart from the medial epicondyle, the ulnar nerve can also get trapped in other places:

    1. Arcade of Struthers: this is a musculofascial band approximately 8cm proximal to the medial epicondyle arching from the medial head of triceps to the medial intermuscular septum.
    2. Near the cubital fossa: the ulnar nerve can sometimes get trapped in between the heads of flexor carpi ulnaris. This is called cubital tunnel syndrome.
    3. Guyon’s canal: this is a bony canal between the pisiform and the hook of the hamate bone in the carpal tunnel. Bike riders and people operating pneumatic drills are often prone to compression here.

     

    Additional examination points for suspected radial nerve pathology

    The radial nerve is a long and complicated nerve with innervations to many muscles. It supplies the entire posterior compartments of the arm and forearm. Radial nerve palsy is sometimes synonymous with Saturday night palsy. A classical history is a young patient who has spent the night slumped on his arm only to wake up with a wrist drop (ironically probably on Sunday morning). This is due to compression of the radial nerve around the humerus and most often self-resolves. However, all radial nerve palsies do not simply have wrist drop! When examining the radial nerve, it is important to consider the locations it can get damaged:

    1. Axilla – historically from old style crutches, causing a complete radial nerve palsy including loss of triceps power and reflex
    2. Humerus – depending on where along the humerus the radial nerve is damaged, the clinical picture will differ slightly:
      1. Nerve damaged at upper third: complete paralysis including triceps
      2. Nerve damaged at middle third: this is Saturday night palsy and preserves triceps power and reflex but brachioradialis function (and therefore supinator reflex) is lost.
      3. Nerve damaged at lower third: here triceps and brachioradialis (and both triceps and supinator reflexes) are preserved. Everything distal in the posterior forearm compartment is affected.
      4. Elbow – here the radial nerve gives off the deep branch of the radial nerve to extensor carpi radialis longus. This muscle alone can extend the wrist and therefore wrist drop will not be a feature. Instead, the patient would not be able to extend the fingers at the MCPJs causing finger drop.
      5. Forearm – here the superficial radial nerve, which is entirely sensory to the web space on the dorsal hand is compressed. Also known as Wartenberg syndrome.

     

    Finally, understanding the mechanics of movement can help reduce unnecessary work up of simple radial nerve palsies. If a patient were to present with wrist drop, the other nerves should of course be examined to exclude mononeuritis multiplex or brachial plexopathy. When wrist drop is present, poor technique can provide falsely positive signs resulting in needless investigations and anxiety for both patient and doctor. When testing for finger abduction (“spread your fingers”), a patient with wrist and finger drop will have weak abduction if the hand is left in the dropped position. This is simply because finger abduction is strongest with the fingers in the plane of the palm, due to the anatomy of the muscles. This is not due to a concomitant ulnar nerve palsy! Likewise, power grip is often used as a crude test of median nerve function. Power grip, however, requires the radial nerve to bolster the wrist in firm extension to counteract the powerful finger flexors supplied by the median nerve. A person with wrist drop will suddenly have normal power grip if the wrist is manually hyperextended for them, thus avoiding a false diagnosis of concomitant median nerve neuropathy!

     

    Summary:

    The upper limb neurological examination should begin with a proper introduction. Then proceed to inspect for signs of neurologic disease. A recommended starting manoeuvre is to test for pronator drift but then move onto to formal testing of tone, power, reflexes, coordination and sensation. Decide if the lesion is an upper or lower motor neurone lesion. If there is a lower motor neurone lesion, decide if this is in a myotome, peripheral nerve, neuromuscular junction or muscle. Brachial plexus lesions can give mixed peripheral nerve type pictures so be aware of this diagnosis. Finally, complete the examination by offering to examine the lower limbs and cranial nerves. Report your findings with a view to delineate where the lesion is in the neuroanatomical axis, then proceed to suggest aetiologies for the clinical syndrome the patient has. 

    References

     

    1) Fig 1: http://meded.ucsd.edu/clinicalmed/neuro2.htm

    2) Fig 2: http://www.aafp.org/afp/2009/0501/p793.html

    3) Fig 3: Postgrad Med J 2002;78:625 doi:10.1136/pmj.78.924.625

    4) Fig 4: http://www.sciencedirect.com/science/article/pii/S0161475405001053

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