190 



MUSCLES OF THE HEAD AND NECK. 



two is lodged the tonsil. The constricted passage between the anterior pillars, 

 leading from the mouth to the pharynx, is called the isthmus of the fauces. 

 The soft palate is acted on by five pairs of elongated muscles, two superior, 

 one in the middle, and two inferior. Of the two inferior pairs of muscles, 

 one is common to the palate and tongue, the other to the palate and 

 pharynx. 



The palato-glossus or constrictor isthmi faucium occupies the anterior 

 pillar of the fauces. Superiorly it is anterior to all the other muscles of the 

 velum, and its fibres are continuous with those of its fellow of the opposite 

 side ; inferiorly, it is lost on the side of the tongue. 



Fig. 165. Fig- 165. DIAGRAMMATIC VIEW OP THE 



MUSCLES IN THE ANTERIOR WALL AND 

 SJDESOF THE PHARYNX, FROM BEHIND. J 



The posterior wall of the pharynx has 

 been divided by a vertical incision in 

 the middle line, and the cut edges drawn 

 to the side so as to expose the nasal, 

 buccal, and laryngeal openings into the 

 pharynx, a, is above the cut surface of 

 the basilar part of the occipital bone, 

 and below that are the posterior nares ; 

 b, upon the cut petrous bone, points by 

 a line to the cartilage of the Eustachian 

 tube of the right side ; c, the back of 

 the ramus of the lower jaw ; d, the 

 posterior border of the thyroid cartilage ; 

 e, middle of the upper part of the cricoid 

 cartilage; /, base of the tongue in the 

 buccal aperture above the epiglottis ; g, 

 lower end of the cavity of the pharynx 

 leading down into the gullet ; 1 , supe- 

 rior constrictor of the pharynx seen from 

 within, and part of the middle con- 

 strictor ; 2, palato-pharyngeus descend- 

 ing to its insertion in the pharynx and 

 thyroid cartilage ; 2', the lower part 

 of the same muscle, on the right side, 

 the upper having been removed ; 3, 

 placed on the internal pterygoid muscle, 



points to the levator palati ; 4, the circumflexus palati muscle on the right side descend- 

 ing from the navicular fossa, and winding round the pulley-like groove of the hamular 

 process into the palate; 5, the retractor or azygos uvulae muscles; above e, the transverse 

 arytenoid muscle, and below it on each side the posterior crico-arytenoid muscle. 



The palato-pharyngeus, occpyuing the posterior pillar of the pharynx, 

 arises in the soft palate by fibres connected with those of the opposite side, 

 and passing partly above and partly below the levator palati and azygos 

 muscles. As the muscle descends it becomes greatly expanded, and its 

 fibres are found extended from the posterior cornu of the thyroid cartilage, 

 back to the middle line of the pharynx posteriorly. 



The azygos uvula (Morgagni) so called from having been supposed to be 

 a single muscle, consists of two slips arising, one on each side of the middle 

 line, from the tendinous structure of the soft palate, and, sometimes, from 

 ihe spine of the palate-plate, and descending into the uvula. The two slips 

 are separated by a slight interval above, and unite as they descend. 



The levator palati arises from the extremity of the petrous portion of the 

 temporal bone, in front of the orifice of the carotid canal, and from the 

 cartilaginous part of the Eustachian tube. Approaching the middle line as it 



