Each dermatome is given a number that matches its pair of spinal nerves.

The doctor will test your dermatomes on each side for light touch, usually done with a cotton ball…

…and a light pinprick, usually done with a safety pin.

Your doctor may first test your face so that you know what “normal” feels like. Each dermatome is scored 0, 1, or 2. For light touch a score of 0 means no feeling, 1 means less feeling than your face, and 2 means the same amount of feeling as your face.

For pinprick 0 means not being able to tell the difference between sharp and dull, 1 means being able to tell sharp from dull, but the pin is felt as less sharp than on your face, and 2 means the same sharpness as your face.