Buccal nerve

At a glance

English

Buccal nerve

Latin (TA2)

Nervus buccalis

System

Nerve

Region

Head

Side

Paired, left and right

About the buccal nerve

The buccal nerve, sometimes called the long buccal nerve, is the one sensory branch of the anterior division of the mandibular nerve, itself part of the trigeminal nerve. It carries feeling from the cheek, both from the skin on the outside and from the mucous membrane on the inside, and from the gum on the cheek side of the lower molar teeth. It must not be confused with the facial nerve's buccal branches, which are motor and reach the same area.

From its origin deep to lateral pterygoid, the nerve passes forwards between the upper and lower heads of that muscle. It then runs downwards and forwards beneath the tendon of temporalis and under cover of masseter, in front of the ramus of the mandible, to reach the outer surface of buccinator. There it breaks into branches. Some pierce buccinator to supply the mucosa of the cheek and the buccal gum of the lower second and third molars; others spread in the skin over the muscle and link up with facial nerve branches there.

The meeting of the two nerves on buccinator reflects a general rule of the head. The trigeminal nerve, through its mandibular division, supplies the muscles of chewing, while the facial nerve supplies the muscles of facial expression. Buccinator is a muscle of expression, so it is moved by the facial nerve, even though the buccal nerve of the trigeminal passes through it on its way to the mucosa. The buccal nerve may carry a few motor fibres to lateral pterygoid as it passes, but it has no motor role in the cheek.

Dentists block the nerve when working on the cheek-side gum and mucosa of the back lower teeth, for instance when a rubber dam clamp must sit on a molar or when a lower molar is extracted. The standard inferior alveolar block does not reach this gum, so a second small injection is placed just behind and to the cheek side of the last molar, only 1 to 2 mm deep because the nerve lies just under the lining. A cut made over the lower jaw's external oblique ridge can injure it.

Course and supply

Arises from

The anterior division of the mandibular nerve (V3) in the infratemporal fossa, often sharing a short stem with the nerve to lateral pterygoid.

Ends in

Branches on the outer surface of buccinator into cutaneous twigs to the cheek and twigs that pierce the muscle to reach the oral mucosa.

Supplies

Sensory to the skin of the cheek, the buccal mucosa and the buccal gingiva of the lower molars; may give small twigs to lateral pterygoid.