Nervous Examination- Motor pathways

This is the order in which I do the motor examination

Inspection

Before anything else, as with any other examination, you should inspect the limbs for wasting, fasciculations, deformities (e.g. claw hand) etc.

Tone

The tone of a limb is its resistance to passive movement.  A patient can be

  • hypotonic
    • loose and floppy
    • usually indicating a lower motor neuropathy (there may be other symptoms like muscle wasting, weakness, hyporeflexia)
  • hypertonic (of which there are two major types)
    • Spasticity
      • Velocity dependent resistance to passive movement, sometimes described as a ‘catch’ at the beginning of passive movement
      • usually indicating an upper motor neuropathy (there may be other symptoms of weakness, hyperreflexia, extensor plantars and clonus)
    • Rigidity
      • Sustained resistance throughout the range of movement, most easily detected on slow movement
      • A sign of basal ganglia dysfunction (Parkinson’s disease)- the rigidity can be described as:
        • ‘Lead-pipe’ rigidity- i.e. a constant resistance
        • ‘Cog-wheel’ rigidity- in the presence of a parkinsonian tremor, there is alternating rigidity that causes a jerking passive movement.
    • Clonus is another form of hypertonicity characterised by a series of rhythmic contractions brought on by sudden stretch of the muscles.  Normal individuals have a degree of clonus but sustained clonus beyond 2/3 contractions is usually pathological.

Tone can be assessed by

  1. Ask the patient to go floppy and let you move their limbs.
  2. In the upper limb, hold the patient’s right hand in yours and support their elbow with your left
    1. To test for rigidity, slowly move the elbow and wrist through their ROM.
    2. To test for spasticity, quickly extend the elbow (spasticity in flexion is usually less pronounced) and/or supinate the forear
  3. In the lower limb
    1. To test for rigidity, begin by rolling the legs on the bed then slowly move the ankle through its ROM.
    2. To test for spasticity, rapidly flex the knee.
  4. To test for clonus, rapidly dorsiflex the ankle (with the leg fully extended) and maintain the force, feeling for any pulsatile contractions in the leg muscles.

Reflexes

(Deep)- Patients may have normal, quick (hyperreflexia), slow (hyporeflexia- this is harder to distinguish from normal) or no (areflexia) reflexes.

  • Hyperreflexia is usually a sign of upper motor neuropathy.
  • Conversely, hypo-/ areflexia is a sign of lower motor neuropathy.

(superficial)- Superficial reflexes usually are used to detect upper motor neuron lesions.  They are either normal or abnormal.

Reflexes are assessed using a tendon hammer.  It is important to make sure the patient (and their limbs) are relaxed.

  1. In the upper limb
    1. Biceps jerk (C5 (C6))- hold the elbow with your opposite hand with your thumb in the cubital fossa.  Strike your thumb with the tendon hammer and look for contraction on the anterior compartment of the arm.                     
    2. Triceps jerk (C6/7)- with the patient’s arms crossed over their chest, or with you suspending their arm with your same hand (so that it is loosely flexed), strike the arm just above the olecranon process and observe for contractions in the posterior compartment of the arm.                  
    3. Supinator jerk ((C5) C6)(brachioradialis)- with the patient’s hand resting on their abdomen, strike the base of the wrist and observe for contraction of the forearm.
  2. In the lower limb
    1. The knee jerk (L3/4)- either with the patient’s legs hanging off the bed or supported with your arm under the knee, strike the knee just below the patella (patellar tendon) and observe for contraction of the quadriceps.
    2. The ankle jerk (S1)- with the patient’s knee slight flexed and leg externally rotated (with your other hand supporting the foot), strike the achilles tendon (heel) and observe for contraction of the posterior compartment of the leg.
  3. Superficial reflexes
    1. Using the point of the tendon hammer, run the point up the plantar aspect of the foot, beginning laterally (and proximally- near the heel) and moving up the lateral aspect of the foot then working medially across the pad of the foot.  A normal response is flexion of the big toe and adduction of the toes.  An abnormal (Babinski sign) is extension and abduction.

Power

Testing power can be a good way of localising a lesion.  Power should be tested proximally first, working your way distally.  Power can be ranked out of 5.

  • 0/5 is no contraction
  • 1/5 is muscle contraction (twitch) with no movement
  • 2/5 is muscle contraction with movement but NOT able to defeat gravity
  • 3/5 is muscle contraction with movement, able to overcome gravity but not resistance from examiner
  • 4(+/-)/5 is muscle contraction with movement and able to overcome degrees of resistance by the examiner
  • 5/5 normal power

Test each movement individually by supporting the joints across the movements with your hand where possible.  Test each movement on each side as you go, comparing each there and then.

In the upper limb-

  • Shoulder abduction/adduction (patient holding arms out like wings)
    • C5 – deltoid (abduction)
    • C6, 7, 8 (adduction)
  • Elbow flexion/extension (flexed elbow to shoulder)
    • C5 / 6 – biceps (flexion) (musculocutaneous)
    • C6 / 7 / 8 – triceps (extension) (radial)
  • Wrist flexion/extension (hold wrist)
    • C7/8 (extension) (radial)
  • Grip
    • Finger flexion (C8) (median)
  • Finger abduction (C8/T1)
    • Little finger (ulnar nerve)
    • 1st finger (radial)
    • Thumb opposition (medial)

In the lower limb

  • Hip flexion (push down on the thigh to avoid testing knee extension simultaneously- with the patient on the bed, ask them to raise their leg)
    • Flexion- L1 /2 (femoral) (psoas major)
  • Hip extension (ask the patient to push their heel and leg into the bed- you try and lift from the heel as it gives you more leverage)
    • Extension- L5 / S1 (gluteal) (gluteal muscles)
  • Hip adduction and adduction (ask the patient to push against your hand- hand should be on the lower thigh)
    • Adduction (L2) (Obturator)
  • Knee flexion/extension (knee bent- pull in towards/push out away from the body)
    • Flexion – L5/S1 (sciatic) (hamstrings)
    • Extension – L3/ 4 (femoral) (quadriceps)
  • Ankle dorsiflexion
    • L4/5 (peroneal) (anterior compartment of the leg)
  • Ankle plantarflexion
    • S1/2 (tibial) (gastrocnemius)
  • Big toe extension
    • L5

Coordination (If necessary)

  • Heel shin test
    • run the heel down the opposite shin
  • Finger nose test
    • touch examiners finger then nose alternately
  • Drift
    • Hold out the arms
    • Push on the arms looking for rebound motion
    • Ask to close their eyes, looking for drift
  • ‘Play the piano’
  • Rapid pronation and supination clapping
  • Gait
  • Heel-toe walking
  • Romberg

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