FACE AND FRONTAL REGION OF HEAD 21 



oculi, the quadratus labii superioris, and the zygomaticus, and 

 it is crossed superficially, near the angle of the mouth, by 

 the external maxillary artery. When the structures superficial 

 to it are turned aside, the muscle will be found springing from 

 the canine fossa below the infra-orbital foramen. It passes 

 downwards to the angle of the mouth, where it blends with the 

 orbicularis oris, some of its fibres passing into the lower lip 

 (Fig. 3). It is an elevator of the angle of the mouth and 

 is supplied by the facial nerve. 



M. Buccinator. The buccinator muscle occupies the 

 interval between the maxilla and the mandible and forms a 

 most important part of the substance of the cheek. Above, 

 it springs from the alveolar border of the maxilla, in the 

 region of the molar teeth. Below, it arises from the 



FIG. 6. Arrangement of the Fibres of the Buccinator Muscles 

 at the Angles of the Mouth. 



alveolar border of the mandible, also in the region of the 

 molar teeth, and, posteriorly, it is attached to the pterygo- 

 mandibular raphe, which forms a bond of union between 

 the buccinator and the superior constrictor of the pharynx. 

 The last-mentioned attachment will be seen to better advantage 

 when the wall of the pharynx is studied (p. 286). Anteriorly, 

 the fibres of the buccinator converge towards the angle of 

 the mouth, where they blend with the orbicularis oris, of 

 which they form a large part. The manner in which the 

 fibres enter the orbicularis must be carefully noted. The 

 upper and lower fibres pass directly to the corresponding 

 lips ; the middle fibres, on the other hand, decussate at the 

 angle of the mouth, so that the lower fibres of the series 

 enter the upper lip, whilst the higher fasciculi reach the 

 lower lip (Fig. 3). 



The buccinator muscle is not classified as a muscle of 

 mastication, but it is used during mastication to prevent food 

 in 2Z> 



