454 ARTERIES. 



The Posterior Auricular Artery (Fig. 276) is a small vessel which arises from 

 the external carotid, above the Digastric and Stylo-hyoid muscles, opposite the 

 apex of the styloid process. It ascends, under cover of the parotid gland, to 

 the groove between the cartilage of the ear and the mastoid process, immediately 

 above which it divides into two branches, an anterior, passing forwards to anas- 

 tomose with the posterior division of the temporal ; and a posterior, communi- 

 cating with the occipital. Just before arriving at the mastoid process, this 

 artery is crossed by the portio dura, and has beneath it the spinal accessory 

 nerve. 



Besides several small branches to the Digastric, Stylo-hyoid, and Sterno- 

 mastoid muscles, and to the parotid gland, this vessel gives off two branches, 



Stylo-mastoid. Auricular. 



The stylo-mastoid .branch enters the stylo-mastoid foramen, and supplies the 

 tympanum, mastoid cells, and semicircular canals. In the young subject, a 

 branch from this vessel forms, with the tympanic "branch from the internal 

 maxillary, a vascular circle, which surrounds the auditory meatus, and from 

 which delicate vessels ramify on the rnembrana tympani. 



The auricular branch is distributed to the back part of the cartilage of the ear, 

 upon which it ramifies minutely, some branches curving round the margin of 

 the fibro-cartilage, others perforating it', to supply its anterior surface. 



The Ascending Pharyngeal Artery (Fig. 279), the smallest branch of the external 

 carotid, is a long slender vessel, deeply seated in the neck, beneath the other 

 branches of the external carotid and the Stylo-pharyngeus muscle. It arises 

 from the back part of the external carotid, near the commencement of that vessel, 

 and ascends vertically between the internal carotid and the side of the pharynx, 

 to the under surface of the base of the skull, lying on the Rectus Capitis Anti 

 cus Major. Its branches may be subdivided into three sets : 1. Those directed 

 outwards to supply muscles and nerves. '2. Those directed inwards to the 

 pharynx. 3. Meningeal branches. 



The external branches are numerous small vessels, which supply the Recti 

 Antici muscles, the sympathetic, hypoglossal and pneurnogastric nerves, and 

 the lymphatic glands of the neck, anastomosing with the ascending cervical 

 artery. 



The pharyngeal branches are three or four in number. Two of these descend 

 to supply the Middle and Inferior Constrictors and the Stylo-pharyngeus, rami- 

 fying in their substance and in the mucous membrane lining them. The largest 

 of the pharyngeal branches passes inwards, running upon the Superior Con- 

 strictor, and sends ramifications to the soft palate, Eustachian tube, and tonsil, 

 which take the place of the ascending palatine branch of the facial artery, Avhen 

 that vessel is of small size. 



The meningeal branches consist of several small vessels, which pass through 

 foramina in the base of the skull, to supply the dura mater. One, the posterior 

 meningeal, enters the cranium through the foramen lacerum posterius with the 

 internal jugular vein. A second passes through the foramen lacerum medium; 

 and occasionally a third through the anterior condyloid foramen. They are all 

 distributed to the duru mater. 



The Temporal Artery (Fig. 276), the smaller of the two terminal branches of 

 the external carotid, appears, from its direction, to be the continuation of that 

 vessel. It commences in the substance of the parotid gland, in the interspace 

 between the neck of the condyle of the lower jaw and the external meatus, 

 crosses over the root of the zygoma, immediately beneath the integument, and 

 divides about two inches above the zygomatic arch into -two branches, an ante- 

 rior and a posterior. 



The anterior temporal inclines forwards over the forehead, supplying the 

 muscles, integument, and pericranium in this region, and anastomoses with the 



