THE PHARYNX. 505 



mination of their alveolar processes, to the cornua of the os 

 hyoides, the side of the thyroid and of the cricoid cartilage; 

 and below it is continued into the oesophagus. In consequence 

 of these several attachments the pharynx is kept open, or, in 

 other words, its sides are prevented from collapsing, and it is 

 drawn up and down in the motions of the tongue and of the 

 larynx. 



The Pharynx consists in three coats: an external one, formed 

 by three muscles, on each side, one above the other, and called 

 constrictors; an intermediate cellular' coat; and an internal mu- 

 cous one. 



1. The Musculus Constrictor Pharyngis Inferior, arises from 

 the side of the cricoid, and from the whole length of the side of 

 the thyroid cartilage. From these points its fibres diverge to 

 the middle vertical line on the back of the pharynx, where they 

 join with their congeners of the opposite side. The lower 

 fibres are nearly if not completely horizontal, and those above 

 increase successively in their obliquity upwards, so that the 

 upper ones are extremely oblique, and reach, at their termina- 

 tion, to within twelve or fourteen lines of the upper part of the 

 pharynx. 



2. The Constrictor Pharyngis Medius, arises from the cornu 

 and appendix of the os hyoides, and from the ligament connect- 

 ing the posterior end of the latter with the upper cornu of the 

 thyroid cartilage. Its inferior margin is overlapped by the su- 

 perior margin of the last; its fibres there are also horizontal, 

 and, indeed, somewhat convex downwards; while the superior 

 fibres become successively more oblique in ascending. It is 

 inserted by the middle line behind, into its fellow of the oppo- 

 site side, and by its point above into the cuneiform process of 

 the os occipitis, just in advance of the recti majores muscles. 



3. The Constrictor Pharyngis Superior, arises from the ptery- 

 goid processes of the sphenoid bone, at their lower end ; and 

 below them from the back part of the upper and under jaws be- 

 hind the last molar teeth, it is also connected at its anterior 

 margin with the buccinator muscle, and with the root of the 

 tongue between the anterior and the posterior half arches of 



VOL. I. 43 



