Oral medicine: 8. orofacial sensation and movement

Specialist referral may be indicated if the Practitioner feels:

Sensory innervation of the mouth, face and most of the scalp depends on the fifth cranial (trigeminal) nerve, so that disease affecting this nerve can cause sensory loss or orofacial pain, or indeed both, sometimes with serious implications. The trigeminal nerve also provides motor supply to the muscles of mastication.

The facial (seventh cranial) nerve controls the muscles of facial expression, so that lesions of the nerve (lower motor neurone lesions) or its central connections (upper motor neurone lesions) can lead to facial weakness. The facial nerve also carries nerve impulses to the tear glands, to the salivary glands, and to the stapedius muscle of the stirrup bone (the stapes) in the middle ear and also transmits taste from the anterior tongue, so that lesions involving this nerve may also affect taste and hearing, lacrimation and salivation.

It is evident, therefore, that dental surgeons should be able to carry out examination of these and other cranial nerves as shown in Table 1.