58 TOPOGRAPHIC AND APPLIED ANATOMY. 



FIG. 21. The pharynx, opened longitudinally from behind, with the three anterior communications: with the nasal 



cavities, with the mouth, and with the larynx. 



Rosenmiiller. It lies upon the firm base furnished by the occipital bone at the base of the skull, 

 a relation which is favorable for the extirpation of this tonsil. Diseases of the pharyngeal tonsil, 

 particularly the proliferations of childhood, may involve the middle ear through the Eustachian 

 tube and lead to suppuration in this situation. 



The pars oralis communicates anteriorlv with the mouth through the isthmus of the fauces. 

 A study of a median section (Plate 4) will make it clear to the reader that, although unpleasant to 

 the living subject, the finger may be introduced into the mouth and passed above the soft palate , 

 palpating its upper surface, the vomer, the surroundings of the choanae, and the posterior pharyn- 

 geal wall with the pharyngeal tonsil. It will also be understood that in the so-called posterior 

 rhinoscopy, a mirror introduced behind the soft palate will show the choanae and the turbinated 

 bones as seen from behind. 



The laryngeal portion of the pharynx (pars laryngea) is below the pars oralis and leads 

 anteriorly into the larynx. It extends to the level of the sixth cervical vertebra, where the 

 pharynx ends and the esophagus commences.. The aditus ad laryngem (superior aperture of the 

 larynx) is bounded above by the edge of the epiglottis and laterally by the aryepiglottic (aryteno- 

 epiglottic] folds, in which the more or less prominent cuneiform and corniculate tubercles (formed 

 by the underlying cartilages of the same name) may be seen with the laryngoscope. Posteriorly 

 in the median line, the laryngeal entrance ends at the interarytenoid notch, the seat of predilection 

 for the slit-like erosions of chronic laryngitis and for tubercular ulcers. The pharyngo-epiglottic 

 folds extend from the pharynx to the border of the epiglottis. The pyrijorm sinuses are situated 

 internal to the alae of the thyroid cartilage, and in their upper portions may be seen a fold of 

 mucous membrane (plica nervi laryngei) produced by the underlying superior laryngeal nerve. 



A loose connective tissue, rich in lymphatic vessels and containing several lymphatic glands 

 at the level of the upper cervical vertebras, connects the posterior wall of the pharynx to the 

 prevertebral fascia, which is separated from the spinal column by only the thin layer of the pre- 

 vertebral muscles (longus capitis et colli muscles). During the act of deglutition the pharynx 

 moves upon this loose connective tissue (see Fig. 26). This tissue is the seat of retro pharyngeal 

 abscess, which may produce dysphagia and dyspnea by pressing upon the pharynx, the choanae, 

 the soft palate, the laryngeal entrance, and the trachea. When these abscesses are favorably 

 located, they may be opened from the oral cavity. Since this loose connective tissue accom- 

 panies the esophagus into the thoracic cavity, it forms a path along which a retropharyngeal 

 abscess may extend downward into the mediastinum, come in contact with the pleura, and either 

 break into the pleural cavity (see Plate 8, b) or lead to pericarditis by extending to the pericardium 

 (see Fig. 51). The relation of the pharynx to the cervical vertebras makes it possible to diagnos- 

 ticate vertebral fractures and dislocations by inspection and palpation through the oral cavity; 

 for example, from the relation of the anterior arch of the atlas to the posterior pharyngeal wall (see 

 Plate 4) it is clear that when the atlas is dislocated anteriorly it may be recognized as a hard 

 prominence in the posterior pharyngeal wall. It will also be readily understood that diseases of 

 the cervical vertebras (such as caries) may lead to retropharyngeal abscess or to perforation and 



