THE PHARYNX. 



443 



the mucoiis membrane, in the neighbourhood of the guttural opening, the nasal 

 cavities, and the Eustachian tubes. Lorge has described a lymphoid gland, 

 analogous to the pharyngeal amygdalae described by KoUiker, at the bottom of 

 the diverticulum between the Eustachian tubes. 



2. Fibrous layer. — This is also named the pharyngeal aponeurosis. It com- 

 mences at the base of the cranium, is first seen on the posterior face of the 

 pharynx, then it passes beneath the muscular layer, where it gradually becomes 

 thinner. It is attached infcriorly to the cartilages of the larynx, and to a 

 fibrous cord that separates the pharynx from the a>sophagus. 



3. Muscular layer. — This is composed of six pairs of muscles, indicated in 



Fig. 251. 



PHARYXX OF THE HORSE (POSTERIOR VIEW). 

 T, Trachea ; t, thyroid gland ; O, oesophagus ; e, e. Eustachian tubes, divided near their termination in 

 the pharynx. 1, Pterygo-pharyngeus, or superior constrictor ; 2, 2, stylo-pharyngeal muscles ; 

 3. 3, great cornua of the os hyoideus ; 4, hyo-pharyngeus, or middle constrictor; 5, 5, thyro- 

 pharyngeus, or thyroid fasciculus of the inferior constrictor; 6, crico-oesophageus ; 7, superior 

 longitudinal oesophageal muscle ; 8, origin of the oesophagus ; 9, posterior crico-arytaenoid muscle. 



the following enumeration : the palato-pharyngeus, pterygo-pharyngeus^ hyo- 

 pharyngeus, thyro-pharyngeus, rrico-pharyngeufi, sfylo-pharyngeus. 



Palato-pharyngeus (Pharyngo-sfaphylinus). — This muscle, which has 

 already been described as belonging to the soft palate, is prolonged backwards 

 on the lateral wall of the pharynx, where its fibres are mixed with those of the 

 pterygo-pharyngeus, and go to be attached to the superior border of the thyroid 

 cartilage, by passing beneath the hyo-pharyngeus and thyro-pharyngeus muscles. 



