222 Anatomy of Skeleton 



attached. But behind the level of the external plate, where the bony surface does not 

 give origin to the muscle but is in contact with it, the wing is seen to narrow sharply 

 to the posterior angle, where it bears the spine, to which the long internal lateral liga- 

 ment of the mandible is fastened. Along the postero-internal edge the Tensor palati 

 arises, and immediately external to this are the lower openings of the oval and spinous 

 foramina. 



Examine this region on the skull. The basal aspect of the bone is continuous 

 with that of the eminentia articularis on the temporal squamous, and the inferior 

 temporal crest is continued back on the temporal to run into the front border of the 

 anterior zygomatic root : evidently all this basal area is in relation with the External 

 Pterygoid as this passes to its insertion into the neck and capsule of the lower jaw, 

 and the muscle covers the bone as far out as the lower temporal ridge : hence the 

 Temporal muscle, coming down over the ridge, makes the immediate outer relation of 

 the External Pterygoid (Fig. 182). 



FIG. 182. The upper left figure shows on the base of the skull the course of some of the branches of the 

 mandibular nerve. A is the basal surface of the great wing, in relation with the upper surface of ex- 

 ternal Pterygoid, and the middle deep temporal and masseteric nerves are seen crossing this surface, 

 therefore between it and the muscle. The temporal nerve reaches the inferior temporal crest and thus 

 the deep aspect of the Temporal muscle, but the nerve to the Masseter, lying a little further back, 

 passes behind the Temporal tendon (giving a posterior deep temporal nerve to the muscle) and lies 

 along the eminentia articularis, in contact with the articular capsule ; it thus reaches the back part of 

 its muscle. The auriculo-temporal nerve runs backwards and outwards, between the sphenoidal 

 spine (long internal ligament) and the capsule (short internal lig.), and then turns out in contact with 

 the back of the capsule, below the Glaserian fissure. The Tensor palati separates the issuing mandi- 

 bular nerve from the Eustachian tube which issues just internal to the spine. The figure on the right is 

 a scheme of the planes, on coronal section, in the pterygoid region. A is the plane of the deep temporal 

 vessels, B of the (deep) temporal nerve, and C of the inferior dental and lingual nerves. Observe that, as can 

 be appreciated in the previous figure, the external Pterygoid is in relation externally with the Temporal 

 tendon and coronoid process of the mandible: thus the long buccal nerve, piercing the muscle, comes 

 into relation externally with the Temporal and can give an anterior deep temporal nerve to its front 

 part ; when it comes forward from under the tendon it appears superficially from under the Masseter, 

 as can be seen from the figure, and lies on Buccinator (see Fig. 206). The lower figures show the 

 relations of nerves, etc., in the region of the foramen lacemm and cavernous sinus. The sinus is 

 removed in one drawing to show the structures deep to it, and its formation is shown in the other. 

 Compare with Fig. 181. Description in text, p. 225. 



Now follow the course of the nerves that run directly out from the mandibular 

 nerve : they must lie between the bone and the Pterygoid muscle. The arrangement 

 of the deep temporal filaments is very variable, but a typical one would have a middle 

 deep temporal running by itself outward and a little forwards from the foramen ovale ; 

 a line showing its course would cross the basal aspect of the great wing and would just 

 lie on the temporal bone as it reached the temporal ridge, turning round this to run 

 up on the deep surface of the Temporal muscle. The bone is sometime? grooved 

 by the nerve near the ridge. The masseteric nerve runs behind the other and more 

 directly outward, thus passing on to the front part of the eminentia articularis after 

 a shorter course on the sphenoid : on the eminence it runs out to the back of the 

 Masseter, passing behind the Temporal tendon and giving a posterior deep temporal 

 filament up along the tendon (Fig. 182). 



The structures passing through the foramina are evidently placed between the 

 Tensor palati and the External Pterygoid. 



Now examine the position of the spine of the sphenoid. Being on the extreme 

 angle of the wing, it lies immediately in front of the inner end of the Glaserian fissure, 

 and the chorda tympani coming out of the fissure runs on to the surface of the Tensor 

 palati by passing to the inner side of the spine, where it may make a groove (groove 

 of Lucas}. Thus the spine has the long ligament fastened to its tip, the chorda tympani 

 on its inner side and the auriculo-temporal nerve passing back between it and the 

 proper capsule of the joint (Fig. 182). 



