THE NECK, ANTERIOR. 125 



sides of the posterior nares, mouth, and larynx ; behind, it 

 rests upon the prevertebral fascia ; and below, is continued 

 into the oesophagus. For the (Esophagus, see Thorax. 



The Pharyngeal Plexus. 



This is a loose meshed plexus of fine nerve filaments 

 formed upon the outer surface of the middle and inferior 

 constrictor muscles by nerve fibres from the glossopharyn- 

 geal, pneumogastric, and superior cervical ganglion. 



Inferior Constrictor. 



Origin. From the side of the cricoid cartilage, from the 

 inferior cornu, the oblique line, and the upper border of 

 the thyroid cartilage. 



Insertion. Into the fibrous raphe of the pharynx. Its 

 lower fibres pass horizontally, the upper, obliquely upward, 

 backward, and inward. 



The recurrent laryngeal nerve passes upward under the 

 lower border of the muscle, and the superior laryngeal per- 

 forates the thyrohyoid membrane above the upper border 

 of the muscle. 

 Middle Constrictor. 



Origin. From both cornua of the hyoid bone and the 

 stylohyoid ligament. 



Insertion. Into the median raphe of the pharynx. Its 

 fibres run to the insertion ; the lower, downward ; the 

 middle, horizontally ; the upper, upward. It is overlapped 

 below by the inferior constrictor and in turn overlaps the 

 superior above. 



Superior Constrictor. 



Origin. From the side of the tongue and mucous 

 membrane, from the posterior portion of the mylohyoid 

 ridge, the pterygomaxillary ligament, and the hamular 

 process and lower portion of the internal pterygoid plate. 



