THE (ESOPHAGUS. 343 



and passes outwards to the petrous portion of the temporal. It is 

 strengthened in the middle line by a strong band descending between 

 the recti antici muscles from a part of the basilar process of the occipital 

 bone (which often presents a marked tubercle). 



The pharjTix is usually described as du-ectly attached superiorly to the loasilar 

 jn-ocess of the occipital bone ; it is certain, however, from dissections in both 

 young and old subjects, that the recti capitis antici muscles come quite forward 

 to the anterior extremity of the basilar process ; that the posterior wall of the 

 pharynx at its uj^per end forms a cul-de-sac on each side opposite the tip of the 

 petrous bone, and lies in a curve, with its convexity forwards, in front of the 

 recti muscles ; and that the only connection of the pharynx with the occipital 

 bone is by means of the mesial band, which has just been described, and which 

 forms a cranio-pharjaigeal ligament (Cleland). The tubercle from which this 

 band principally springs is sometimes named tuherculum. lyliartjiujcum. 



Behind, the pharynx is loosely connected by areolar tissue to the 

 prevertebral fascia covering the bodies of the cervical vertebra and the 

 muscles which rest upon them. At the sides it has similar connections 

 with the styloid process and its muscles, and with the large vessels 

 and nerves of the neck. In front, it is attached in succession to the 

 sides of the posterior nares, the mouth and the larynx. Thus, com- 

 mencing above by a tendinous structure only, at the petrous portion 

 of the temporal bone and the Eustachian tube, the pharynx is con- 

 nected by means of muscle and fibrous membrane, first, with the 

 internal pterygoid plate, then with the pterygo-maxillary ligament, and 

 next with the mylo-hyoid ridge of the lower jaw; below this, it is 

 attached to the sides of the tongue, to the hyoid bone, and stylo- 

 hyoid ligament ; and, still lower down, to the thyroid and cricoid 

 cartilages. 



Structure.— The muscles of the pharynx are the superior, middle 

 and inferior constrictors, the stylo-pharyngeus, and the palato-pharyn- 

 geus. They are already described. 



The mucous membrcme is continuous at the several apertures with 

 that of the adjacent cavities. It varies somewhat in its character in 

 different parts. Its upper portion is thick where it adheres to the base 

 of the skull, but much thinner near the entrance of the Eustachian 

 tubes and the posterior nares: in this situation numerous racemose 

 mucous gkinds are found collected in a layer beneath the mucous mem- 

 brane ; lymphoid follicles also exist throughout the whole of the phaiynx. 

 A collection of these, forming a glandular mass similar to that forming 

 the tonsils, stretches across the back of the pharyngeal cavity between 

 the orifices of the two Eustachian tubes (Kolliker). In the part opposite 

 the fauces, the mucous membrane exactly resembles that of the mouth. 

 Lower down it becomes paler, and at the back of the larynx it forms 

 several longitudinal folds. According to Henle, the epithelium upon 

 the upper portion of the pharynx, as low down as a horizontal line level 

 with the floor of the nares, is columnar and ciliated ; but, below that 

 point, it is squamous and destitute of cilia. 



THE (ESOPHAGUS. 



The asopMrjus or gullet, the passage leading from the pharynx to 

 the stomach, commences at the cricoid cartilage opposite the lower 

 border of the fifth cw-vical vertebra (sixth, Braune), and descending 

 along the front of the spine, passes through the diaphragm opposite the 



