Motor Assessment

People, and by people I mean textbook authors, make this unnecessarily complex and time-consuming.

It need not be this way.


In the arms, test the following as your basic toolkit:

  • Shoulder Abduction (good test of proximal power)
  • Elbow Flexion/Extension
  • Wrist Extension (radial nerve)
  • Finger Extension (great test of distal power)
  • Finger Abduction (ulnar nerve)
  • Thumb Abduction (median nerve)

In other words, it’s one at the shoulders, two and the elbow, one at the wrist, two and the fingers and one at the thumb. 1…2….1….2…1.

All the other stuff you do in the upper limbs is fluff – and generally pointless.

Yes, that’s right, shoulder adduction = pointless; wrist flexion = pointless. You aren’t adding anything and are testing a mixture of nerves and myotomes. So why bother?

Next, look for patterns, and describe them – unilateral or bilateral? symmetrical or asymmetrical? proximal? distal? global? pyramidal? (more of that in a moment)

If you are going to describe weakness, just go with three terms:

  • mild
  • moderate
  • severe

In an exam setting, you might have to grade it with the generally useless MRC scale for weakness. If you are going to torture yourself with this, for crying out loud don’t add a load of “+” and “-” signs to it!

  • 5 – normal
  • 4 – weak, but some ooommphff needed to overcome the patient
  • 3 – very weak, you can beat them with little effort
  • 2 – so weak that the power would only be useful to an astronaut
  • 1 – a flicker only
  • 0 – well, need I really tell you?

At least that way, I know what you mean when you write it down or ring me up.

A word on "pyramidal" weakness, if I may. 

It took me ages to understand this. Basically, if you mess with the pyramidal tract (motor cortex - white matter - brainstem - spinal cord) then you get a "pyramidal" pattern of weakness. In the upper limb, this means the flexors are stronger than the extensors, and your upper limb adopts a flexed posture (see image). In contrast, the opposite happens in the leg - which is handy if you need to use your leg of support (otherwise you would see loads of patients hopping around with a flexed leg!). Just think of a patient with a long-standing hemiplegic stroke and picture them - it helps.



The legs are easier than the arms.

  • Hip Flexion/Extension
  • Knee Flexion/Extension
  • Ankle Dorsiflexion/Plantar flexion
  • (you can skip the big toe, usually)

That means 2 at the hip, 2 at the knee and 2 at the ankle.

Ideally, you should see your patient walk. This is a great time saver (especially if you are a busy GP. You can test proximal power by getting the patient to squat and stand up again, and test distal power by getting the patient to walk on tip-toe and on their heels.

As the meerkat says …


Here is a good example of how to do it, courtesy of our most excellent NuMED students.

The diagnosis? Well, that would be telling, wouldn’t it?

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