THE (ESOPHAGUS. 891 



recesses, the walls of which are surrounded by lymphoid tissue similar to what is 

 found in the tonsils. Across the back part of the pharyngeal cavity, between the 

 two Eustachian tubes, a considerable mass of this tissue exists, and has been named 

 the pharyngeal tonsil. Above this in the middle line is an irregular, flask-shaped 

 depression of the mucous membrane, extending up as far as the basilar process of 

 the occipital bone. It is known as the bur 8 a pharyngca, and was regarded by 

 Luschka as the remains of the diverticulum, which is concerned in the development 

 of the anterior lobe of the pituitary body. Other anatomists believe that it is 

 connected with the formation of the pharyngeal tonsils. 



The muscular coat has been already described (page 328). 



Surgical Anatomy. The internal carotid artery is in close relation with the pharynx, so 

 that its pulsations can be felt through the mouth. It has been occasionally wounded by sharp- 

 pointed instruments introduced into the mouth and thrust through the wall of the pharynx. 

 In aneurism of this vessel in the neck the tumor necessarily bulges into the pharynx, as this is 

 the direction in which it meets with the least resistance, nothing lying between the vessel and 

 the mucous membrane except the thin Constrictor muscle, whereas on the outer side there is 

 the dense cervical fascia, the muscles descending from the styloid process, and the margin of the 

 Sterno-mastoid. 



The mucous membrane of the pharynx is very vascular, and is often the seat of inflamma- 

 tion, frequently of a septic character, and dangerous on account of its tendency to spread to the 

 larynx. On account of the tissue which surrounds the pharyngeal wall being loose and lax, the 

 inflammation is liable to spread through it i'ar and wide, extending downward into the posterior 

 mediastinum along the oesophagus. Abscess may form in the connective tissue behind the 

 pharynx, between it and the vertebral column, constituting what is known as retro-pharyngeal 

 abscess. This is most commonly due to caries of the cervical vertebrae, but may also be caused 

 by suppuration of a lymphatic gland which is situated in this position opposite the axis, and 

 which receives lymphatics from the nares, or by a gumma or by acute pharyngitis. In these 

 cases the pus may be easily evacuated by an incision, with a guarded bistoury, through the 

 mouth, but, for aseptic reasons, it is desirable that the abscess should be opened from the neck. 

 In some instances this is perfectly easy ; the abscess can be felt bulging at the side of the neck 

 and merely requires an incision for its relief, but this is not always so. and then an incision 

 should be made along the posterior border of the Sterno-mastoid and the deep fascia divided. 

 A director is now to be inserted into the wound, the forefinger of the left hand being introduced 

 into the mouth and pressure made upon the swelling. This acts as a guide, arid the director is 

 to be pushed onward until pus appears in the groove. A pair of sinus forceps are now inserted 

 along the director and the opening into the cavity dilated. 



Foreign bodies not infrequently become lodged in the pharynx, and most usually at its termi- 

 nation at about the level of the cricoid cartilage, just beyond the reach of the finger, as the dis- 

 tance from the arch of the teeth to the commencement of the oesophagus is about six inches. 



THE (ESOPHAGUS. 



The oesophagus, or gullet, is a muscular canal, about nine inches in length, ex- 

 tending from the pharynx to the stomach. It commences at the upper border of 

 the cricoid cartilage, opposite the intervertebral disk between the fifth and sixth 

 cervical vertebrae, descends along the front of the spine through the posterior medi- 

 astinum, passes through the Diaphragm, and, entering the abdomen, terminates at 

 the cardiac orifice of the stomach opposite the tenth dorsal vertebra or the inter- 

 vertebral disk between the tenth and eleventh dorsal vertebrae. The general direc- 

 tion of the oesophagus is vertical, but it presents two or three slight curves in its 

 course. At its commencement it is placed in the median line, but it inclines to the 

 left side as far as the root of the neck, gradually passes to the middle line again, 

 and finally again deviates to the left as it passes forward to the oesophageal open- 

 ing of the Diaphragm. The oesophagus also presents an antero-posterior flexure, 

 corresponding to the curvature of the cervical and thoracic portions of the spine. 

 It is the narrowest part of the alimentary canal, being most contracted at its com- 

 mencement and at the point where it passes through the Diaphragm. 



Relations. In the neck the oesophagus is in relation, in front, with the trachea, 

 and at the lower part of the neck, where it projects to the left side, with the thy- 

 roid gland and thoracic duct ; behind, it rests upon the vertebral column and Longi 

 colli muscles ; on each side, it is in relation with the common carotid artery (espe- 

 cially the left, as it inclines to that side) and part of the lateral lobes of the thy- 

 roid gland ; the recurrent laryngeal nerves ascend between it and the trachea. 



