438 TOPOGRAPHICAL ANATOMY. 



masseter. 5. Below, n. lingualis, ram. mylohyoid., n. dental, 

 infer., m. pterygoid. internus ; above, between the last and max- 

 illa super. : art. maxillar. intern., nn. dental, infer, and tem- 

 poral, superfic., lig. laterals internum, which separates the prece- 

 ding from ram. lingualis n. trigemini. 



[Dissection. 1. Carry an incision through the skin, only, from the inner 

 angle of the eyelids along the lower border of the orbit to the outer angle of 

 the lids, thence parallel with the zygoma to its temporal root. 2. An inci- 

 sion from the inner angle of the eyelids to the commissure of the lip, then to 

 the anterior border of the masseter muscle upon the inferior maxillary bone, 

 and thence parallel with the lower edge of the horizontal ramus of this bone 

 to its angle. Reflect the skin towards the sterno-cleido-mast. m., and dissect 

 the parts 1, 2, and 3. 



Dissect away carefully the parotid gland, leaving it attached by its duct. 



Now, saw through the temporal root of the zygoma and the malar bone, 

 divide the fascias attached to the zygoma above, and reflect it, together with 

 the masseter muscle, carefully, downwards. The parts, 4., will be exposed, 

 the vessels and nerves close to the posterior border of the temporal muscle. 

 Detach the masseter from its insertion, and leave it suspended by its nerve. 

 The insertion of the temporal muscle (the coronoid process of the lower jaw) 

 is now to be sawn through, and, with the muscle, turned upwards. The 

 pterygoid muscles are exposed, and the parts, 5., may be dissected. Two 

 incisions are required to remove the coronoid process ; one, vertical, parallel 

 with the posterior border of the ascending ramus, and passing through the 

 centre of the incisura sigmoidalis ; the other, transverse, and parallel with 

 the border of the alveolus. The two incisions should meet in about the cen- 

 tre of the ascending ramus. TRANS.] 



Pars intermaxillaris the anterior portion of the cheek ; be- 

 tween the upper and lower jaws. 



e. Floor of the mouth. The tongue with ihefrenulum, on the 

 sides of which, close beneath the tongue the openings of the ductus 

 WTiarton., at the sides of the tongue artt. ranince, and more exter- 

 nally vena ranince. Mm. mylokyoid. shuts in the cavity of the 

 mouth ; below it the anterior belly of biventer, the skin. 



[Dissection. To examine these parts and their relations accurately, it is 

 necessary, after removing the skin and displaying the soft parts, to make a 

 vertical section of the lower jaw, on the outer side of, not through, the sym- 

 physis ; in fact, between the lower incisor teeth and first cuspidatus. Then, 

 dividing the mucous membrane of the mouth at its attachment to the lower 

 jaw, the tongue may be drawn forwards, and the anatomy of this region stu- 

 died. A bristle may be passed through the duct (Wharton's) of the submax- 

 illary gland. The openings of the sublingual glands by the sides of the 

 tongue should also be examined. TRANS.] 



