Dermatomes should be tested for any sensory disturbance that correspond to involvement of certain nerve root levels. This test should be done with the patient in a seated position. The examiner needs to make sure to test all dermatomes by running a relaxed hand over the patients head, covering the sides and back of the head, down over the shoulder, upper chest and back, and then down the arms to hands and fingertips. If a difference is noted between both sides the examiner can also use a pinwheel, pin, cotton batting or brush to map out the are of sensory differences. Note: Sensory deficits could also be caused by peripheral nerve impairments or other neurological deficits (Magee 2007).