facial sensation
Last reviewed 01/2018
The three divisions of the fifth nerve - ophthalmic, maxillary, mandibular - are tested individually.
Test light touch all three division. Ask the patient to keep his eyes closed and to say 'yes' each time the touch of the cotton wool is felt. Do not stroke as the stimulus should be punctate.
Only assess pinprick if indicated as it is painful. Use a new pin each time. Apply a light but consistent stimulus. Any area of changed sensation should be mapped, passing from regions of dull sensation to sharp.
Note that an upper lesion of the spinal cord may cause a dissociated sensory loss of the face. This is because pain and temperature sensation terminate in the spinal tract nucleus of the upper cervical cord. This contrasts with touch and proprioceptive fibres which run from the pontine nucleus to form the trigeminothalamic tract.