SPECIAL ANATOMY. 187 



downwards this process, we expose the guttural pouch. 

 This is a dilated pouch, lined by a transparent mucous 

 membrane in which we may see vessels ramifying, and 

 which has an opening anteriorly situated, a long slit in 

 the wall of the Eustachian tube, which here degenerates 

 into a mere groove between two cartilaginous ^prominences, 

 dilated inferiorly. It is visible as far as foramen sty- 

 loideum, and inferiorly is the only source of communi- 

 cation between the pharynx and the guttural pouch. The 

 outer and lower corner of the anterior surface of the i^ouch 

 is bounded by hyo-pharyngeus, situated between stylo- 

 pharyngeus and palato-pharyugeus ; here also we see the 

 parotid lymphatic g-lands. Posteriorly the guttural pouch 

 presents the superior attachment of the recti capitis antici 

 muscles, on the outer side of which are large nerves and 

 the internal carotid artery. The pouch along the central 

 line lies in contact with its fellow. It jDresents numerous 

 papillae on its internal surface. By cutting through the 

 posterior pillar of the tongue we now expose the isthmus 

 of the fauces. This is the passage which runs from the 

 base of the tongue to the epiglottis. Anteriorly it is 

 bounded by the opening between the posterior pillars 

 of the tongue, posteriorly by the opening, on either 

 side of which are the pillars of the fauces, which are 

 composed of muscular fibres running directly from the 

 jDterygoid process to the thyroid cornu, surrounded by 

 mucous membrane, much thickened by addition of salivary 

 glandular structure. The roof of this passage is formed by 

 the soft palate, which consists of a fixed and pendulous 

 portion. The fixed portion is attached anteriorly and late- 

 rally to the crescentic posterior margin of the ossa palati. 

 It consists of a fibrous layer, the superior surface of which 

 is covered by pharyngeal mucous membrane, the inferior 

 separated by a muscular layer and salivary glandular 

 structure from the mucous membrane of the fauces. This 

 muscular layer, palato-pharyngeus, runs from the fibrous 

 layer and from the pterygoid process, to blend with its 

 fellow at the central line of the pharynx, and to become 

 attached to the thyroid cornua. The fibrous layer is also 

 acted upon by 



Tensor palati, which arises from the styloid process of 

 the petrous temporal bone in common with stylo- 

 pharyngeus, runs forwards along the side of the Eustachian 



