This is the muscle of the cheek.
The buccinator forms the muscular component of the cheek and is used every time air expanding the cheeks is forcefully expelled. It is in the space between the mandible and the maxilla, deep to the other facial muscles in the area.

The buccinator arises from the posterior part of the maxilla and mandible opposite the molar teeth and the pterygomandibular raphe, which is a tendinous band between the pterygoid hamulus superiorly and the mandible inferiorly and is a point of attachment for the buccinator and superior pharyngeal constrictor muscles.

The fibers of the buccinator pass toward the corner of the mouth to insert into the lips, blending with fibers from the orbicularis oris in a unique fashion. Central fibers of the buccinator cross so that lower fibers enter the upper lip and upper fibers enter the lower lip. The highest and lowest fibers of the buccinator do not cross and enter the upper and lower lips, respectively.

Contraction of the buccinator presses the cheek against the teeth. This keeps the cheek taut and aids in mastication by preventing food from accumulating between the teeth and the cheek. The muscle also assists in the forceful expulsion of air from the cheeks.

Origin

  • Lateral surface of alveloar processes of the maxilla and mandible at the level of the third molar tooth.
  • Anterior side of pterygomandibular raphe (posterior side of pterygomandibular raphe gives origin to superior constrictor muscle of the pharynx.)

Insertion

All the fibres converge at the angle of the mouth. Upper fibres go to the upper lip and join with those of the opposite side. Lower fibres go to the lower lip and joins with those of the opposite side. Middle fibres decussate near the angle of the mouth. The lower part of the middle fibres reach the upper lip. The upper part of the middle fibres reach the lower lip. All the fibres fuse with the fibres of the orbicularis oris.

Nerve supply

Buccal branch of the facial nerve.

Actions

It compresses the cheek against the teeth. This action is required during the process of chewing, when the food accumulates with in the vestibule of the mouth. It helps in sucking by compressing the cheek. Its action is required to blow the cheek. This muscle is covered by the bucco pharyngeal fascia and buccal pad of fat. It is pierced by the parotid duct.