1598 HUMAN ANATOMY. 



front and back walls are probably in contact. In the female several of these distances 

 are smaller. Thus the pharynx is in horizontal sections at most levels a transverse 

 cleft. 



The naso-pharynx, broad from side to side and short from before backward, 

 passes insensibly into the oro-pharynx when the soft palate is not raised so as to cut 

 off communication. Anteriorly are the nasal openings, described with the nose. 

 The separation of the two regions on the lateral wall is determined by the naso- 

 pharyngeal fold which runs from the base of the skull to the beginning of the soft 

 palate. This fold is very irregular in course and development. It occasionally is 

 grooved so as to present a furrow. Sometimes the furrow takes the place of the fold 

 and at other times the fold joins that in front of the opening of the Eustachian tube. 

 This orifice is on a level with the end of the inferior turbinate bone and less than 

 I cm. behind it. It is usually a triangular opening without a distinct border below, 

 although it may be oval or even round. The longest diameter is about i cm. The 

 end of the cartilage of the tube curves over the top of the opening from the front 

 and descends along its posterior border, producing a strong fold of the mucous mem- 

 brane, the saipi7igo-pharyngeal, which descends to be lost in the lateral wall of the 

 oro-pharynx, or even sooner. The salpingo-palatine fold in front of the opening of 

 the Eustachian tube is, as a rule, less prominent and very variable. It is formed 

 above by the bent end of the cartilage, and below by a small band of fibrous tissue, 

 the salpingo-palatine ligament, running from the cartilage into the soft palate. The 

 fossa of Rosenmiiller is a deep pocket at the angle of the pharynx between the 

 posterior wall and the back of the projection of the cartilage of the tube. Its anterior 

 and posterior walls are almost in contact and are often connected by accidental 

 adhesions. This is the broadest part of the naso-pharynx. Adenoid collections — the 

 tubal tonsils — are found in varying degree about the orifice of the tube, especially 

 over the fold behind it. The belly of the levator palati muscle makes a prominence 

 in the lateral wall below the tubal orifice. 



The oro-pharynx opens into the mouth at the anterior pillar of the fauces. 

 The posterior pillar, covering the palato-pharyngeus muscle, runs down the side of 

 the pharynx as the palato-pharyngeal fold. It may be traced to the base of the 

 superior horn of the thyroid cartilage, or, as is most common, it is lost on the lateral 

 wall a little higher. The pharyngo-epiglottic fold above mentioned arises from the 

 front of the epiglottis near the lateral edge and runs upward and backward across 

 the pharynx. It may end soon, or it may reach the palato-pharyngeal fold, or, 

 crossing this, may extend even as far as the salpingo-pharyngeal one. It contains 

 muscular or tendinous fibres from the stylo-pharyngeus. If well marked, it may 

 bound below the niche containing the tonsil. The anterior wall of the oro-pharynx 

 is formed, the mouth being closed, by the posterior vertical part of the tongue. The 

 respiratory tract, passing through the nose, and the digestive, passing through the 

 mouth, cross each other in the oro-pharynx, so that the former is the anterior below 

 this point. 



The laryngo-pharynx, the lowest part of the pharynx, is, roughly speaking, 

 the part below the level of the hyoid bone. It is separated from the oro-pharynx 

 by the pharyngo-epiglottic fold. In the middle of it is the opening of the larynx 

 behind the epiglottis and enclosed by the aryteno-epiglottic and interarytenoid folds. 

 The sinus pyrrformis is a depression on either side of the entrance of the larynx 

 between the aryteno-epiglottic fold and the arytenoid cartilage internally and a part 

 of the great wing of the thyroid cartilage and the thyro-hyoid membrane externally. 

 It is open behind. The thin mucous membrane lining the sinus has a transverse 

 fold, formed by the superior laryngeal nerve, in front between the hyoid bone and 

 the thyroid cartilage. The lower part of the palato-pharyngeal fold is seen in frozen 

 sections near the superior horn of the thyroid cartilage at the lateral aspect of the 

 cleft, which is all that appears of the pharynx. The anterior wall behind the aryte- 

 noid cartilages and the structures between them slants backward as it descends. 

 Behind the cricoid cartilage it is vertical. Here the pharynx narrows to join the 

 oesophagus. 



The mucous membrane of the pharynx is smooth, except for the elevations 

 caused by collections of lymphoid follicles. It is more loosely attached and more 



