Motor System Examination of the motor system often takes place during the examination of the limbs. The first portion of the examination of the motor system involves observation. You need to specifically look for atrophy of muscles and for spontaneous movement in the muscles, both of which suggest lower motor neuron dysfunction. Normally bulk of muscles is fairly well maintained in an upper motor neuron lesion. Next, you need to examine for tone.
Tone is examined by assessing the patient response to passive movement.
In the upper extremity, you ask the patient to relax the limbs, and then you move the forearm through the range of motion of the elbow, looking for continuous or variable resistance to movement. When you are learning to assess for tone, you just have to practice. You have to feel a lot of normal people before you'll know what it feels like when it's not normal. So, when you are a learner in physical diagnosis, take the time to try this out on a lot of normal people. To assess for tone in the lower extremities, the patient should be supine on a bed.