OCCIPITAL POSTERIOR AURICULAR PHARYNGEAL. 377 



being covered by the Sterno-mastoid, Splenius, Digastric, and Trachelo-mastoid 

 muscles, resting upon the Complexus, Superior oblique, and Kectus posticus major 

 muscles ; it then ascends vertically upwards, piercing the cranial attachment of the 

 Trapezius, and passes in a tortuous course over the occiput, as high as the vertex, 

 where it divides into numerous branches. 



The branches given off from this vessel are the 



Muscular. Inferior meningeal. 



Auricular. Arteria princeps cervicis. 



The muscular branches supply the Digastric, Stylo-hyoid, Sterno-mastoid, 

 Splenius, and Trachelo-mastoid muscles. The branch distributed to the Sterno- 

 mastoid is of large size. 



The auricular branch supplies the back part of the concha. 



The meningeal branch ascends with the internal jugular vein, and enters the 

 skull through the foramen lacerum posterius, to supply the dura mater in the 

 posterior fossa. 



The arteria princeps cervicis (fig. 212) is a large branch which descends along 

 the back part of the neck, and divides into a superficial and deep branch. The 

 former runs beneath the Splenius, giving off branches which perforate that muscle 

 to supply the Trapezius, anastomosing with the superficial cervical artery ; the 

 latter passes beneath the Complexus, between it and the Semi-spinalis colli, and 

 anastomoses with the vertebral, and deep cervical branch of the superior intercostal. 

 The anastomosis between these vessels serves mainly to establish the collateral 

 circulation after ligature of the carotid or subclavian artery. 



The cranial branches of the occipital artery are distributed upon the occiput ; 

 they are very tortuous, and lie between the integument and Occipito-frontalis, 

 anastomosing with the artery of the opposite side, the posterior auricular, and 

 temporal arteries. They supply the back part of the Occipito-frontalis muscle, the 

 integument, pericranium, and one or two branches occasionally pass through the 

 parietal or mastoid foramina, to supply the dura mater. 



The POSTERIOR AURICULAR ARTERY (fig. 209) 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 Avhich it divides into two branches, an anterior, which passes forwards to 

 anastomose with the posterior division of the temporal ; and a posterior, which 

 communicates 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-mas- 

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



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 maxil- 

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

 delicate vessels ramify on the membrana tympani. 



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

 upon which it minutely ramifies, some branches curving round its margin, others 

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



The ASCENDING PHARYNGEAL ARTERY (fig. 212), 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 Stylo-pharyngeus muscle. It arises 

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

 and passes up to the under surface of the base of the skull, ascending the neck 

 between the internal carotid and the side of the pharynx, and lying on the 



