BUCCINATOR. PTKRYGOIDEI. 177 



nal pterygoid muscle, a part of the buccinator, and the internal maxil- 

 lary artery with its deep temporal branches. 



By sawing through the coronoid process near to its base, and pull- 

 ing it upwards, together with the temporal muscle, which may be dis- 

 sected from the fossa, we obtain a view of the entire extent of the 

 buccinator and of the external pterygoid muscle. 



The BUCCINATOR (buccina, a trumpet), the trumpeter's muscle, arises 

 from the alveolar process of the superior maxillary and from the ex- 

 ternal oblique line of the inferior maxillary bone, as far forward as 

 the second bicuspid tooth, and from the pterygo-maxillary ligament. 

 This ligament is the raphe of union between the buccinator and 

 rior constrictor muscle, and is attached by one extremity to the hamu- 

 lar process of the internal pterygoid plate, and by the other to th 

 extremity of the molar ridge. The fibres of the muscle converge to- 

 wards the angle of the mouth where they cross each other, the 

 superior being continuous with the inferior segment of the orbicularis 

 oris, and the inferior with the superior segment. The muscle is in- 

 vested externally by a thin fascia. 



Relations. By its external surface^ posteriorly with a large and 

 rounded mass of fat, which separates the muscle from the ramus of 

 the lower jaw, the temporal, and the masseter ; anteriorly with the 

 risorius Santorini, the zygomatici, the levator anguli oris, and the 

 depressor anguli oris. It is also in relation with a part of Stenon's 

 duct which pierces it opposite the second molar tooth of the upper 

 jaw, with the transverse facial artery, the branches of the facial and 

 buccal nerve, and the facial artery and vein. By its internal surface 

 with the buccal glands and mucous membrane of the mouth. 



The EXTERNAL PTERYGOID is a short and thick muscle, broader at 

 its origin than at its insertion. It arises by two heads, one from the 

 pterygoid ridge on the greater ala of the sphenoid ; the oilier from the 

 external pterygoid plate and tuberosity of the palate bone. The fibre 

 pass backwards to be inserted into the neck of the lower jaw and the 

 interarticular fibro-cartilage. The internal maxillary artery frequently 

 passes between the two heads of this muscle. 



Relations. By its external surface with the ramus of the lower jaw, 

 the temporal muscle, and the internal maxillary artery ; by its internal 

 surface with the internal pterygoid muscle, internal lateral ligament of 

 the lower jaw, arteria meningea media, and inferior maxillary nerve ; 

 and by its upper border with the muscular branches of the inferior 

 maxillary nerve ; the internal maxillary artery passes between the two 

 heads of this muscle, and its lower origin is pierced by the buccal nerve. 



The external pterygoid muscle must now be removed, the ramus of 

 the lower jaw sawn through its lower third, and the head of the bone 

 dislocated from its socket and withdrawn, for the purpose of seeing the 

 pterygoideus internus. 



The INTERNAL PTERYGOID is a thick quadrangular muscle. It 

 arises from the pterygoid fossa and descends obliquely backwards, to 

 be inserted into the ramus and angle of the lower jaw : it resembles 



