BRANCHES OF THE EXTERNAL CAROTID. 559 



facial and auriculo-temporal nerves. Besides some twigs to the parotid gland, the 

 articulation of the jaw, and the Masseter muscle, its branches are the 



Transverse Facial. Middle Temporal. 



Anterior Auricular. 



The transverse facial is given off from the temporal before that vessel quits 

 the parotid gland ; running forward through its substance, it passes transversely 

 across the face, between Stenson's duct and the lower border of the zygoma, and 

 divides on the side of the face into numerous branches, which supply the parotid 

 gland, the Masseter muscle, and the integument, anastomosing with the facial, 



-teric. and infra-orbital arteries. This vessel rests on the Masseter, and is 

 accompanied by one or two branches of the facial nerve. It is sometimes a branch 

 of the external carotid. 



The middle temporal artery arises immediately above the zygomatic arch, and, 

 perforating the temporal fascia, supplies the Temporal muscle, anastomosing with 

 the deep temporal branches of the internal maxillary. It occasionally gives off 

 an orbital branch, which runs along the upper border of the zygoma, between 

 the two lavers of the temporal fascia, to the outer angle of the orbit. This 

 branch supplies the Orbicularis palpebrarum, and anastomoses with the lachrymal 

 and palpebral branches of the ophthalmic artery. 



The anterior auricular branches are distributed to the anterior portion of the 

 pinna, the lobule, and part of the external meatus, anastomosing with branches 

 of the posterior auricular. 



Surgical Anatomy. It occasionally happens that the surgeon is called upon to perform 

 the operation of arteriotomy upon this vessel in cases of inflammation of the eye or brajn. If 

 the student will consider the relations of the trunk of this vessel as it crosses the zygomatic arch 

 with the surrounding structures, he will observe that it is covered by a thick and dense fascia. 

 1 by one or two veins, and accompanied by branches of the facial and auriculo-tem- 

 poral nerves. Bleeding should not be performed in this situation, as much difficulty may arise 

 from the dense fascia over the vessel preventing a free flow of blood, and considerable pressure 

 is requisite afterward to repress the haemorrhage. Again, a varicose aneurism may be formed 

 by the accidental opening of one of the veins in front of the artery, or severe neuralgic pain 

 may arise from the operation implicating one of the nervous filaments in the neighborhood. The 

 anterior branch, on the contrary, is subcutaneous, is a large vessel, and is readily compressed : it 

 should consequently always be selected for the operation. 



The Internal Maxillary (Fig. 350), the larger of the two terminal branches of 

 the external carotid, passes inward, at right angles from that vessel, to the inner 

 side of the neck of the condyle of the lower jaw, to supply the deep structures of 

 the face. At its origin, it is imbedded in the substance of the parotid gland, 

 being on a level with the lower extremity of the lobule of the ear. 



In the first part of its course (maxillary portion} the artery passes horizontally 

 forward and inward, between the ramus of the jaw and the internal lateral lig- 

 ament. The artery here lies parallel with the auriculo-temporal nerve ; it crosses 

 the inferior dental nerve, and lies along the lower border of the External 

 ptervgoid muscle. 



In the second part of its course (pterygoid portion) it runs obliquely forward 

 and upward upon the outer surface of the External ptervgoid muscle, being 

 covered by the ramus of the lower jaw and lower part of the Temporal muscle. 



In the third part of its course (spheno-maxillary portion) it approaches the 

 superior maxillary bone, and enters the spheno-maxillary fossa in the interval 

 between the two heads of the External ptervgoid, where it lies in relation with 

 Meckel's ganglion, and gives off its terminal branches. 



Peculiarities. Occasionally, this artery passes between the two Ptervgoid muscles. The 

 vessel in this case passes forward to the interval between the processes of origin of the External 

 ptervgoid. in order to reach the superior maxillary bone. Sometimes the vessel escapes from 

 beneath the External pterygoid by perforating the middle of that muscle. 



The branches of this vessel may be divided into three groups, corresponding 

 with its three divisions. 



