PHARYNX 283 



as to the styloid process and the muscles which take origin 

 from it ; and the pharyngeal plexus of nerves ramifies over 

 its margin, extends on to its surfaces, and supplies it with 

 motor and sensory twigs. Anteriorly, the pharyngeal wall is 

 interrupted by the openings of the nasal cavities, mouth, and 

 larynx ; and it is from the structures which lie in proximity to 

 those apertures that it derives its principal attachments. From 

 above downwards it is attached, on each side (a) to the 

 medial pterygoid lamina ; (b) to the pterygo-mandibular 

 raphe; (c) to the side of the tongue; (d) to the medial 

 aspect of the mandible ; (e) to the hyoid bone ; (/) to the 

 thyreoid cartilage ; (g) to the cricoid cartilage. Above, it is 

 attached to the basis cranii. The various attachments will 

 be studied more fully when the constituent parts of its walls 

 are dissected. 



It should be recognised that an altogether false idea of 

 the natural form of the pharynx is obtained when it is 

 removed from the vertebral column and is stuffed with tow 

 or other substances. In transverse sections of the frozen 

 body it will be noted that the cavity of the nasal part of the 

 pharynx remains patent under all conditions, whilst at lower 

 levels the anterior wall is more or less nearly approximated 

 to the posterior wall, and below the opening of the larynx the 

 cavity of the pharynx presents the appearance of a simple 

 transverse slit. 



Pharyngeal Wall. The wall of the pharynx consists of 

 four well-marked strata. From without inwards they are : 

 (i) bucco-pharyngeal fascia; (2) pharyngeal muscles; (3) 

 pharyngeal aponeurosis ; (4) mucous membrane. The 

 muscular layer, which is composed of the three constrictor 

 muscles, with the stylo-pharyngeus and pharyngo-palatinus, 

 on each side, must now be dissected. 



Bucco-pharyngeal Fascia. The bucco-pharyngeal fascia 

 is a coating of fibrous tissue which covers both the buccinator 

 and the pharyngeal muscles. 



Dissection. Remove the bucco-pharyngeal fascia and clean 

 the pharyngeal muscles, sweeping the knife in the direction of 

 their fibres. Note the veins which lie between the fascia and 

 the muscles, forming the pharyngeal plexus, and the pharyngeal 

 plexus of nerves to which the pharyngeal branches of the vagug 

 nerve, the glosso-pharyngeal nerve, and the superior cervical 

 sympathetic ganglion have already been traced. The veins 

 and nerves must be removed for the proper display of the muscles. 



