THE VAGO-ACCESSORY MUSCLES. 497 



aponeurosis of the soft palate and from the posterior nasal spine. They pass back- 

 ward and downward, almost parallel with each other, into the uvula to be inserted 

 into its aponeurosis. 



Nerve-Supply. — From the pharyngeal plexus. 



Action. — To raise the uvula. 



4. Palato-Glossus (Fig. 1339). 



Attachments. — The palato-glossus (m. glossopalatinus) is a thin sheet which 

 arises from the under surface of the aponeurosis of the soft palate and descends in 

 the anterior pillar of the fauces (arcus glossopalatinus) to be inserted into the sides 

 of the tongue, mingling with the fibres of the stylo-glosSus; ' '  



Nerve-Supply. — From the pharyngeal plexus, probably by fibres from the 

 anterior part of the nucleus of the spinal accessory nerve. 



Action. — To raise the back part of the tongue and at the same time to narrow 

 the fauces by causing an approximation of the anterior pillars. Acting from below, 

 it will depress the soft palate. 



5. Palato-Pharvngeus (Fig. 509). 



Attachments. — The palato-pharyngeus (m. pharyngopalatinus) arises from the 

 aponeurosis of the soft palate, from the posterior border of the hard palate, and also 

 from the lower portion of the cartilage of the Eustachian tube. It passes downward 

 and backward in the posterior pillar of the fauces (arcus pharyngopalatinus), internal 

 to the superior and middle constrictors of the pharynx, and is inserted into the pos- 

 terior border of the thyroid cartilage and into the posterior w^all of the pharynx. 

 That portion of the muscle which arises from the cartilage of the Eustachian tube is 

 often regarded as a distinct muscle which has been termed the salpingo-pharyngeiis. 



Nerve-Supply. — From the pharyngeal plexus, probably by fibres from the 

 anterior part of the nucleus of the spinal accessory nerve. 



Action. — It draws the pharynx and thyroid cartilage upward and at the same 

 time approximates the two posterior pillars of the fauces. Acting from below, it 

 will depress the soft palate. 



6. Constrictor Pharyngis Superior (Figs. 501, 510). 



Attachments. — The superior constrictor of the pharynx forms a thin quadri- 

 lateral sheet whose origin is closely associated with part of that of the buccinator, 

 there being usually some interchange of fibres between the two muscles. It arises 

 from the lower part of the posterior border of the internal pterygoid plate and 

 from its hamulus, from the posterior border of the pterygo-mandibular ligament, and 

 is thence continued upon the internal oblique line of the mandible, the mucous mem- 

 brane of the mouth, and the side of the tongue. The uppermost fibres pass in a 

 curve backward and upward and are inserted into the pharyngeal tubercle of the 

 occipital bone, while the remainder unite with the muscle of the opposite side in a 

 median raphe on the posterior wall of the pharynx. 



Nerve-Supply. — From the pharyngeal plexus by fibres which probably arise 

 from the anterior portion of the nucleus of the spinal accessory nerve. 



Action. — To compress the pharynx. 



Relations. — Between the uppermost fibres of the muscle and the base of the 

 skull is an interval in which may be seen the levator palati and the Eustachian tube. 

 This interval has been termed the sijins of Morgagni, and is closed by a sheet of 

 connective tissue termed the fascia pharyngobasilaris, which is an upward prolonga- 

 tion to the base of the skull of the pharyngeal portion of the bucco-pharyngeal 

 fascia (page 488). 



Externally the superior constrictor is in relation above with the internal carotid 

 artery, the vagus nerve, and the cervical sympathetic, and below with the upper 

 part of the middle constrictor and the stylo-pharyngeus. Internally it is lined by 

 mucous membrane throughout the greater part of its extent, being in relation, how- 

 ever, with the tonsil and the palato-pharyngeus muscle. 



32 



