60 TOPOGRAPHICAL ANATOMY OF THE 



The first part of the artery lies upon the pharynx and the diverti- 

 culum of the auditory (Eustachian) tube, and is in contact laterally 

 with the submaxillary gland and the jugulo-mandibular, digastric and 

 stylo-hyoid muscles. The following vessels leave this part of the 

 artery : — 



(1) A. glandulce suhmo^xillaris media. — This is a small artery (or 

 arteries) that leaves the external carotid close to its origin and supplies 

 the middle part of the submaxillary gland. 



(2) A. viaxillaris externa. — The external maxillary artery is the 

 largest branch of the external carotid, from which it arises underneath 

 the stylo-hyoid muscle. At first the vessel follows the lower border of 

 the great cornu of the hyoid bone, accompanied by the glosso-pharyngeal 

 nerve above and the hypoglossal nerve below. Then, turning somewhat 

 abruptly downwards, it runs on the medial surface of the internal 

 pterygoid muscle, crossing the hyo-glossal muscle, the hypoglossal nerve, 

 the intermediate tendon of the digastricus and the submaxillary duct, to 

 gain the space between the two halves of the mandible where it has 

 been already dissected (page 12). Its continuation as the facial artery 

 has also been observed. The following are the arteries to which the 

 external maxillary gives origin : — 



(a) The ascending palatine artery (a. palatina ascendens) begins 

 close to the border of the stylo-hyoid muscle and at once passes medial 

 to the glosso-pharyngeal nerve and the stylo-hyal bone. It ramifies in 

 the wall of the pharynx and ends in the soft palate. A small branch 

 (ramus tonsillaris) supplies the tonsil. 



(6) The lingual artern (a. lingualis) is the largest vessel arising 

 from the external maxillary, which it leaves as this artery makes its 

 downward bend. It continues the direction of the parent vessel, that 

 is, along the lower border of the great cornu of the hyoid bone, and 

 passes under the hyo-glossal muscle to reach the tongue, where its 

 subsequent course will be followed during the dissection of that organ. 



(c) Small branches (aa. glandulas submaxillaris inferiores) are 

 furnished to the submaxillary gland as the external maxillary artery 

 passes its anterior end. 



(c?) Numerous small branches (rami musculares) pass into the 

 pterygoid, digastric, sterno-liyoid and omo-hyoid muscles. 



(e) The sublingual artery (a. sublingualis) was seen at an earlier 

 stage of the dissection. 



The second part of the external carotid artery was revealed by the 

 removal of the parotid gland, and it was seen that this portion of the 

 vessel gave origin to the masseteric, posterior auricular and superficial 

 temporal arteries (page 45). 



