01 4 



DISSECTION OF THE PTERYGOID REGION. 



and arteries. 



Internal 

 maxillary 

 artery : 



course and 

 relations ; 



varies in its 

 position. 



Branches 

 are in three 



sets. 



Those be- 

 neath jaw. 



Inferior 

 dental 



lies a 

 branch to 

 mylo-hyoid 

 muscle. 



Great 



meningeal 



artery 



ends in 

 skull ; 



but gives 



branch to 

 tympanum, 



to meatus, 



The large men in geal artery and its offsets are to be sought beneath 

 the external pterygoid. Sometimes the trunk of the internal 

 maxillary artery lies beneath that muscle, and in that case, it and 

 its brandies are now to be cleaned. 



The INTERNAL MAXILLARY ARTERY (fig. 218, 8 ) is one of the 

 terminal branches of the external carotid, and takes a winding 

 course beneath the lower jaw and the temporal muscle to the spheno- 

 maxillary fossa, where it ends in branches for the face, the interior 

 of the nose, and the palate and pharynx. 



At first the artery is directed forwards between the ramus of the jaw 

 and the internal lateral ligament of the joint, and crosses the inferior 

 dental nerve ; it then ascends over the lower portion of the external 

 pterygoid, being placed between it and the temporal muscle ; and 

 finally, it turns inwards opposite the interval between the heads of 

 the external pterygoid to gain the spheno-maxillary fossa. The 

 course of the artery is sometimes beneath, instead of over the exter- 

 nal pterygoid ; and when that is the case, the artery reaches the 

 spheno-maxillary fossa by passing between the heads of the muscle. 



The BRANCHES of this artery are numerous, and are classed in 

 three sets ; the first set arises beneath the jaw : the second between 

 the muscles ; and the third in tlie spheno-maxillary fossa. 



Two chief branches, viz., the inferior dental and the great menin- 

 geal, leave the internal maxillary artery in its first part while it 

 is in contact with the ramus of the jaw. 



The INFERIOR DENTAL ARTERY descends between the internal 

 lateral ligament and the jaw, and enters the foramen on the inner 

 surface of the ramus, along with the companion nerve ; it supplies 

 the molar and bicuspid teeth, and ends in an incisor branch running 

 forwards in the bone to the incisor and canine teeth, and in a small 

 mental branch which issues from the bone through the foramen 

 of that name to end on the face. 



As the artery is about to enter the foramen it furnishes a small 

 mylo-hyoid branch to the muscle of that name ; this is conducted by 

 a groove on the inner surface of the bone, in company with a branch 

 from the dental nerve, to the superficial surface of its muscle, where 

 it anastomoses with the submental artery. 



The GREAT MIDDLE MENiNGEAL ARTERY is the largest branch of 

 the internal maxillary, and arises opposite the preceding. It 

 ascends beneath the external pterygoid muscle, and between the 

 roots of the auriculo-temporal nerve to the foramen spinosum of 

 the sphenoid bone, through which it passes into the skull. Its 

 course and distribution within the cranial cavity have been already 

 seen (p. 514). Before the artery reaches the foramen, it usually 

 furnishes the following small branches ; but one or more of them 

 may arise directly from the internal maxillary trunk : 



a. The TYMPANIC BRANCH passes into the tympanum through 

 the Gkserian. fissure, and is distributed to the tympanic membrane 

 and parts within the tympanic cavity. 



b. A DEEP AURICULAR BRANCH usually arises with the former, 

 enters the meatus through the cartilage or between that and 



