558 THE ARTERIES. 



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 membrana tympani. It anastomoses with the petrosal 

 branch of the middle meningeal artery by a twig which enters the hiatus Fallopii. 



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 

 fibre-cartilage, others perforating it, to supply its anterior surface. It anastomoses 

 with the anterior auricular branches of the temporal. 



The mastoid branch passes backward, over the Sterno-mastoid muscle, to the 

 scalp above and behind the ear. It supplies the posterior belly of the Occipito-fron- 

 talis muscle and the scalp in this situation. It anastomoses with the occipital artery. 



The Ascending Pharyngeal Artery (Fig. 352), 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 anticus major. 

 Its branches may be subdivided into three sets : 



Prevertebral. Pharyngeal. Meningeal. 



The prevertebral branches are numerous small vessels which supply the Recti 

 capitis antici and Longus colli muscles, the sympathetic, hypoglossal, and 

 pneumogastric 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, ramifying 

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

 pharyngeal branches passes inward, running upon the Superior constrictor, and 

 sends ramifications to the soft palate and tonsil, which take the place of the 

 ascending palatine branch of the facial artery when that vessel is of small size. 

 A twig from this branch passes up the Eustachian tube to supply the tympanum. 



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 ; a second 

 passes through the foramen lacerum medium ; and occasionally a third through 

 the anterior condyloid foramen. They are all distributed to the dura mater. 



Surgical Anatomy. The ascending pharyngeal artery has been wounded from the throat, 

 as in the case in which the stem of a tobacco-pipe was driven into the vessel, causing fatal 

 haemorrhage. 



The Superficial Temporal Artery (Fig. 349), the smaller of the two terminal 

 branches of the external carotid, appears, from its direction, to be the continu- 

 ation 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 posterior root of the zygoma, passes beneath the Attra- 

 hens aurem muscle, and divides, about two inches above the zygornatic arch, into 

 two branches, an anterior and a posterior. 



The anterior temporal inclines forward over the forehead, supplying the 

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

 supra-orbital and frontal arteries. 



The posterior temporal, larger than the anterior, curves upward and backward 

 along the side of the head, lying superficial to the temporal fascia, and inosculates 

 with its fellow of the opposite side, and with the posterior auricular and occipital 

 arteries. 



The superficial temporal artery, as it crosses the zygoma, is covered by the 

 Attrahens aurem muscle and by a dense fascia given off from the parotid gland: 

 it is also usually crossed by one or two veins, and accompanied by branches of the 



