308 



THE MUSCLES OF THE HEAD AND NECK. 



sists of scattered fibres which join those of the opposite muscle in the middle line ; 

 the deep or lower layer is much stronger, and partly meets its fellow, partly takes 

 origin from the hinder margin of the hard palate and the aponeurosis of the velum. 

 At the outer border of the soft palate the muscle also receives one or two slender 

 bundles which descend from the lower and fore part of the cartilage of the 

 Eustachian tube (salpingo-pharyngeus, Santorini). It then passes downwards and 

 backwards in the posterior pillar of the fauces, becomes considerably expanded, and 

 is inserted, its fibres mingling with those of the stylo-pharyngeus, into the upper and 

 hinder borders of the thyroid cartilage, and into the fibrous layer of the lower part 

 of the pharynx, reaching as far as, or even crossing, the middle line behind. 



The azygos uvulae muscle (Morgagni), so called from having been supposed to 

 be a single muscle, consists of two slips, which arise, one on each side of the middle 



Fig. 282. DIAGRAMMATIC VIEW OP THE MUSCLES OP 



THE SOFT PALATE, &C., FROM BEHIND. (Allen 



Thomson. ) ^ 



The posterior wall of the pharynx has been divided 

 by a vertical incision in the middle line, and the cut 

 edges dravm to the side so as to expose the nasal, buccal, 

 and laryngeal openings, a, is above the cut surface of 

 the basilar process, and below that are the posterior 

 nares ; b, cartilage of the right Eustachian tube ; c, back 

 of the ramus of the lower jaw ; d, posterior border of 

 the thyroid cartilage ; c, upper part of the cricoid car- 

 tilage ; f, base of the tongue above the epiglottis ; 

 g, lower end of the pharynx leading into the gullet ; 



1, superior constrictor of the pharynx seen from within ; 



2. palato-pharyngeus ; 2', the lower part of the same 

 muscle, on the right side ; 3, placed on the internal 

 pterygoid muscle, points to the levator palati ; 4, the 

 right circumflexus palati muscle winding round the 

 hamular process ; 5, azygos uvulae ; above e, the aryte- 

 noid, and below it on each side the posterior crico- 

 arytenoid muscle. 



line, from the tendinous structure of the soft 

 palate, sometimes also from the posterior 

 nasal spine, and descend into the uvula. 



The two slips are separated by a slight interval above, and unite as they 

 descend. 



The levator palati muscle arises by a narrow tendon from the under surface of 

 the petrous portion of the temporal bone, in front of the orifice of the carotid canal, 

 and from the lower margin of the cartilage of the Eustachian tube. The fibres form 

 a rounded muscle which passes downwards and forwards into the pharynx, crossing 

 the upper border of the superior constrictor. Becoming flattened as it approaches 

 the middle line, its fore part is inserted into the aponeurosis of the palate, while 

 the larger posterior portion meets the muscle of the other side under cover of the 

 azygos uvulae. 



The circumflexus or tensor palati arises from the navicular fossa at the root 

 of the internal pterygoid plate, from the spine of the sphenoid, and from the outer 

 side of the Eustachian tube. Its flattened belly descends perpendicularly, on the 

 mesial side of the internal pterygoid muscle, and ends in a tendon which, turning 

 round the hamular process, where a synovial bursa smooths its passage, extends 

 horizontally inwards, and is inserted into a transverse ridge on the under surface of 

 the palate bone, and into the aponeurosis of the soft palate. 



Nerves. The muscles of this group receive their nerves from sources some of which are 

 not yet sufficiently determined. The tensor palati receives a branch through the otic ganglion 



