BUCCINATOR PTERYGOIDEI. 155 



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

 arises from the alveolar process of the superior maxillary and from 

 the external oblique line of the inferior maxillary bone, as far for- 

 ward as the second bicuspid tooth, and from the pterygo-maxillary 

 ligament. This ligament is the raphe of union between the bucci- 

 nator and superior constrictor muscle, and is attached by one extre- 

 mity to the hamular process of the internal pterygoid plate, and by 

 the other to the extremity of the molar ridge. The fibres of the 

 muscle converge towards 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 invested 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 to 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 pterygoidr idge on the great ala of the sphenoid ; the other from 

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

 fibres 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, and the inferior Fi g- 70 -* 



maxillary nerve ; and by its upper 

 border with the muscular branches of 

 the inferior maxillary nerve ; the in- 

 ternal 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 dislo- 

 cated from its socket and withdrawn, for the purpose of seeing the 

 pterygoideus internus. 



* The two pterygoid muscles. The zygomatic arch and greater part of the ramus 

 of the lower jaw have been removed in order to bring these muscles into view. 1. The 

 sphenoid origin of the external pterygoid muscle. 2. Its pterygoid origin. 3. The 

 internal pterygoid muscle. 



