TEMPORAL AND INFRATEMPORAL REGIONS 267 



required ; it should extend from the centre of the incisura above, down- 

 wards and anteriorly, to the point where the anterior margin of the ramus 

 meets the body of the mandible. First use the saw, and then complete 

 the division with the bone forceps. The bttccinator nerve (O.T. long buccal) 

 and its companion artery are in a position of danger during this dissection, 

 and must be carefully guarded. They proceed downwards and anteriorly 

 under cover of the lower part of the temporal muscle, and not infrequently 

 the nerve traverses its substance. The coronoid process and the temporal 

 muscle must be thrown well upwards, and the muscular fibres separated, 

 by the handle of the knife, from the bone forming the lower part of the 

 temporal fossa. This will bring into view the deep temporal nerves and 

 arteries as they ascend between the cranial wall and the muscle. This is 

 the time to follow the middle temporal artery also. It will be noticed to 

 give branches to the muscle, and it extends upwards upon the squamous part 

 of the temporal bone. The zygomatico-temporal nerve also should be 

 traced to the point where it emerges from the minute aperture on the 

 temporal surface of the zygomatic bone. At this point it lies under cover 

 of the temporal muscle. 



The infratemporal region (O.T. pterygo-maxillary) may now be fully 

 opened up by removing a portion of the ramus of the mandible. Two hori- 

 zontal cuts must be made one through the neck of the mandible, and the 

 other immediately above the level of the mandibular (O.T. inferior dental) 

 foramen. To find the level of the foramen, the handle of the knife should be 

 thrust between the ramus and the subjacent soft parts, and carried down- 

 wards. Its progress will soon be arrested by the entrance of the inferior 

 alveolar vessels and nerve into the foramen, and the lower border of the 

 instrument will correspond with the line along which the bone should be 

 cut. Both incisions should be made with the saw, until the lateral table 

 of the bone is cut through, and then the bone forceps may be employed to 

 complete the division. 



Parts displayed by the above Dissection. When the fat 

 and areolar tissue are removed, the pterygoid muscles will 

 come into view. The external pterygoid extends horizontally 

 to the neck of the mandible. The internal pterygoid, embrac- 

 ing the anterior part of the external pterygoid muscle between 

 its two heads of origin, proceeds downwards and posteriorly 

 upon the deep surface of the ramus of the mandible. It 

 bears very much the same relation to the medial aspect of the 

 ramus that the masseter presents to its lateral surface. The 

 great blood vessel of the space the internal maxillary artery 

 proceeds anteriorlyOpon (frequently under cover of) the 

 external pterygoid muscle. The nerves of the region also will 

 be found in close relationship to the same muscle. Thus, 

 emerging from between its upper border and the cranial wall, 

 at the level of the infratemporal crest, are the masseteric and 

 the two deep temporal nerves ; appearing from under cover of 

 its lower border are the inferior alveolar and the lingual 

 nerves-, whilst the auriculo-temporal nerve is related to its 

 medial surface posteriorly and the buccinator nerve anteriorly. 



