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it divides into two branches, the cerebral carotid and facial carotid 

 arteries. 



During tliis course it gives off the following branches : — 



I. One well marked and sometimes also a smaller artery that 

 supply the esophagus. 



II. A branch that supplies a part of the cervico-mandibularis 

 muscle, the lateral and ventral walls of the pharynx and skin in 

 this region. 



III. A branch (Ramus pterygoideus, Schlemm) which supplies 

 the transverso-maxillo-pterygo-mandibularis, and the cervico- 

 mandibularis muscles and the skin near them. 



IV. The First Spinal Artery (Ramus spinalis, Rathke ; Art. 

 nervi spinalis I, Hofmann) which arises at the same level or 

 slightly in front of the preceding. The vessel passes through the 

 atlanto-occipital membrane between the axis and the basi- occipital 

 bone and, running into the loop of the basilar artery beneath the 

 medulla oblongata, forms an anastomosis with its fellow of the 

 opposite side, a relationship first described by Schlemm (35), who 

 called this vessel the Truncus anonymus. By means of this 

 anastomosis the blood can pass from the left to the right internal 

 carotid. Shortly before piercing the atlanto-occipital membrane 

 this artery gives off two branches : — 



A. A small branch (Ramus pterygoideus, Schlemm) to the 



Pterygo-sphenoidalis m uscles. 



B. A fairly large Occipital artery (Art. occipitalis, Schlemm), 



which however soon divides into two vessels, a small and a 

 large. 



The smaller is the occipital branch (Ramus occipitalis, Schlemm), 

 supplying the muscles and skin of the occipital region. 



The larger is the Cervical Artery (Art. cervicalis, Schlemm), a 

 long and fairly well-marked vessel. It runs backwards 

 near the hypapophyses of the anterior vertebra), covei^ed 

 by the rectus capitus anticus muscles to which it sends 

 small branches, to the fourteenth vertebra. Here it joins 

 with a small branch from the bifurcated extremity of the 

 vertebral artery. During its course it gives off a series of 

 branches that lie beside the spinal nerves, and each of 

 these sends branches not only to the skin and muscles, 

 but also a small one, a spinal artery, that enters the 

 neural canal through the intervertebral foramen. 



"V". The Maxillary At-tery (Art. maxillaris, or dentalis inferior, 

 Rathke ; Art. alveolaiis inferioi-, Schlemm) arises about midway 

 between the spinal artery and the point just behind the orbit 

 where the internal carotid divides. It runs outwards, accompany- 

 ing the inferior maxillary branch of the trigeminal nerve between 

 the second and third parts of the parietali-quadrato-mandibularis 

 muscle, to which it gives branches. After giving off several twigs 

 also to the transverso-maxillo-pterygo-mandibularis muscle, it 

 passes on through the posterior maxillary foramen into the lower 



