210 HEAD AND NECK 



by the glosso-pharyngeal nerve. If the dissector removes the 

 fascia at the posterior part of the thyreo-hyoid space he will 

 expose the lower fibres of the middle and the upper fibres 

 of the inferior constrictor, and in the interval between them, 

 on a deeper plane, the lateral surface of the lower part of 

 the stylo-pharyngeus. It is an elevator of the larynx. 



Dissection. Snip through the base of the styloid process 

 with the bone forceps, and throw it and the attached muscles 

 downwards and forwards. The upper parts of the internal 

 carotid artery and internal jugular vein are now exposed, and 

 the ascending pharyngeal and ascending palatine arteries can 

 be followed to the base of the skull. 



If the external carotid is pushed forwards and the internal 

 carotid is pulled backwards the ascending pharyngeal artery 

 will be seen, in a well-injected subject, lying in the areolar 

 tissue between the two carotid arteries and on a deeper plane. 

 It must be cleaned and followed to the base of the skull. 



Arteria Pharyngea Ascendens. The ascending pharyngeal 

 artery springs from the medial surface of the external carotid 

 artery, close to its lower end, and is its smallest branch. It 

 ascends along the lateral border of the pharynx, lying between 

 the stylo-pharyngeus laterally and the constrictors of the 

 pharynx medially, first in a plane between the external and 

 internal carotid arteries, and then to the medial side of the 

 internal carotid. As it passes upwards it gives pharyngeal 

 branches to the wall of the pharynx, and premrtebral branches 

 to the prevertebral muscles. At the base of the skull it gives 

 off meningeal branches, which enter the cranial cavity through 

 the hypoglossal canal, the jugular foramen, and the foramen 

 lacerum ; and palatine branches, which pierce the pharyngeal 

 aponeurosis, above the upper border of the superior con- 

 strictor, and descend, along the levator veli palatini, to the 

 soft palate. Offsets from the latter branches are given to 

 the auditory tube (O.T. Eustachian) and to the palatine 

 tonsil. 



Arteria Palatina Ascendens. After the ascending pala- 

 tine artery has passed between the stylo-glossus and the stylo- 

 pharyngeus (see p. 205), it ascends, along the side of the 

 pharynx, to the petrous part of the temporal bone. There 

 it pierces the pharyngeal aponeurosis, and then it accompanies 

 the levator veli palatini to the soft palate. It helps to supply 

 the soft palate, the palatine tonsil, the wall of the pharynx, 

 and the auditory tube. 



