

THE PHARYNX 1141 



ot the epiglottis a movement produced by the contraction of the Thyreoarytsenoidei, the 

 Arytsenoidei, and the Arytsenoepiglottidei. 



After leaving the tongue the bolus passes on to the posterior or laryngeal surface of the epi- 

 glottis, and glides along this for a certain distance; then the Glossopalatini, the constrictors of 

 the fauces, contract behind it; the palatine velum is slightly raised by the Levator veil palatini, 

 and made tense by the Tensor veli palatini; and the Pharyngopalatini, by their contraction, 

 pull the pharynx upward over the bolus, and come nearly together, the uvula filling up the 

 slight interval between them. By these means the food is prevented from passing into the nasal 

 part of the pharynx; at the same time, the Pharyngopalatini form an inclined plane, directed 

 obliquely downward and backward along the under surface of which the bolus descends into 

 the lower part of the pharynx. The Salpingopharyngei raise the upper and lateral parts of the 

 pharynx i. e., those parts which are above the points where the Stylopharyngei are attached 

 to the pharynx. 



Mucous Membrane. The mucous membrane of the soft palate is thin, and covered with strati- 

 fied squamous epithelium on both surfaces, excepting near the pharyngeal ostium of the auditory 

 tube, where it is columnar and ciliated. According to Klein, the mucous membrane on the 

 nasal surface of the soft palate in the fetus is covered throughout by columnar ciliated epithelium, 

 which subsequently becomes squamous; some anatomists state that it is covered with columnar 

 ciliated epithelium, except at its free margin, throughout life. Beneath the mucous membrane 

 on the oral surface of the soft palate is a considerable amount of adenoid tissue. The palatine 

 glands form a continuous layer on its posterior surface and around the uvula. 



Vessels and Nerves. The arteries supplying the palate are the descending palatine branch 

 of the internal maxillary, the ascending palatine branch of the external maxillary, and the pala- 

 tine branch of the ascending pharyngeal. The veins end chiefly in the pterygoid and tonsillar 

 plexuses. The lymphatic vessels pass to the deep cervical glands. The sensory nerves are 

 derived from the palatine and nasopalatine nerves and from the glossopharyngeal. 



THE PHARYNX. 



The pharynx is that part of the digestive tube which is placed behind the nasal 

 cavities, mouth, and larynx. It is a musculomembranous tube, somewhat conical 

 in form, with the base upward, and the apex downward, extending from the under 

 surface of the skull to the level of the cricoid cartilage in front, and that of the 

 sixth cervical vertebra behind. 



The cavity of the pharynx is about 12.5 cm. long, and broader in the transverse 

 than in the antero-posterior diameter. Its greatest breadth is immediately below 

 the base of the skull, where it projects on either side, behind the pharyngeal ostium 

 of the auditory tube, as the pharyngeal recess (fossa of Rosenmiiller} ; its narrowest 

 point is at its termination in the esophagus. It is limited, above, by the body 

 of the sphenoid and basilar part of the occipital bone; below, it is continuous with 

 the esophagus; posteriorly, it is connected by loose areolar tissue with the cervical 

 portion of the vertebral column, and the pre vertebral fascia covering the Longus 

 colli and Longus capitis muscles; anteriorly, it is incomplete, and is attached in 

 succession to the medial pterygoid plate, pterygomandibular raphe, mandible, 

 tongue, hyoid bone, and thyroid and cricoid cartilages; laterally, it is connected to 

 the styloid processes and their muscles, and is in contact with the common and 

 internal carotid arteries, the internal jugular veins, the glossopharyngeal, vagus, 

 and hypoglossal nerves, and the sympathetic trunks, and above with small parts 

 of the Pterygoidei interni. Seven cavities communicate with it, viz., the two 

 nasal cavities, the two tympanic caviti.es, the mouth, the larynx, and the esophagus. 

 The cavity of the pharynx may be subdivided from above downward into three 

 parts: nasal, oral, and laryngeal (Fig. 994). 



The Nasal Part of the Pharynx (pars nasalis pharyngis; nasopharynx) lies behind 

 the nose and above the level of the soft palate : it differs from the oral and laryn- 

 geal parts of the pharynx in that its cavity always remains patent. In front (Fig. 

 1029) it communicates through the choanse with the nasal cavities. On its lateral 

 wall is the pharyngeal ostium of the auditory tube, somewhat triangular in shape, 

 and bounded behind by a firm prominence, the torus or cushion, caused by the 

 medial end of the cartilage of the tube which elevates the mucous membrane. 



