DISSECTION OF THE PHARYNX. 655 



of the different structures lying against the pliaryngeal wall from one 

 another and make out their relations from the fresh point of view. 

 The margins of the inferior and middle constrictor muscles are to lower and 

 lie denned. Beneath the lower one, near the larynx, will be found 

 the recurrent nerve with companion vessels ; between the inferior and 

 middle are the superior laryngeal nerve and vessels ; and the stylo- 

 pharyngeus muscle disappear.-; beneath the upper border of the middle 

 constrictor. 



To see the attachment of the superior constrictor to the lower jaw upper con- 

 ami the pterygo-maxillary ligament, it will be necessary to cut stl 

 through the internal pterygoid muscle. Above the upper fibres of 

 this constrictor, and near the base of the skull, are two small muscles 

 of the palate (p and H) entering the pharynx : one, tensor palati, lies 

 close inside the internal pterygoid muscle ; and the other, levator 

 palati, is deeper and larger. 



The PHARYNX is a portion of the alimentary canal which gives Pharynx: 

 passage to both food and air. It is placed behind the nose, mouth 

 and larynx, and extends from the base of the skull to the lower extent ; 

 border of the cricoid cartilage of the larynx, where it ends in the 

 oesophagus on a level with the lower part of the sixth cervical 

 vertebra. In form it is somewhat conical, with the dilated part form ; 

 upwards ; and its length averages about four and a half inches, but length ; 

 varies according to the position of the head and the degree of 

 elevation of the larynx. 



The tube of the pharynx is incomplete in front, where it com- is an incom- 

 municates with the cavities above mentioned, but is closed above, p 

 behind, and at the sides. Below 7 , it opens into the gullet. On each relations ; 

 side of it are placed the trunks of the carotid arteries, with the 

 internal jugular vein, and the accompanying cranial and sympathetic 

 nerves. Behind it is the spinal column, covered by muscles, viz., 

 longi colli and recti capitis antici. 



In front, the pharynx is united to the larynx, the hyoid bone, attach- 

 the tongue, and the bony framework of the nasal fossae, which form mi Qts ' 

 the boundaries of its cavity in this direction. Behind and at the and con- 

 sides, it has a special muscular wall, and is only united by very s 

 loose connective tissues to surrounding parts. At the upper end the 

 bag is completed by a fibrous aponeurosis which fixes it to the base 

 of the skull ; and the whole is lined by mucous membrane. 



The aponeurosis of attachment is seen at the upper part of the Aponeurosi 

 pharynx, where the muscular fibres are absent, to connect the tube of pha 

 to the base of the skull, and to complete the posterior boundary. 

 Superiorly it is fixed to the basilar process of the occipital, and the 

 petrous part of the temporal bone ; but inferiorly it becomes thin, 

 and is lost in the layer of connective tissue between the muscular 

 and mucous strata. On this membrane some of the fibres of the 

 superior constrictor muscle terminate. 



The MUSCLES of the pharyngeal wall are arranged in two layers Muscles in 

 an outer comprising the three constrictors, the fibres of which run 

 more or less transversely to the direction of the tube, and an inner 



