758 



(ESOPHAGUS. 



tion to the sensations of any part, giving rise to 

 emotions on which the mind frequently dwells, 

 may so far modify the nutrition of the part as 

 to become a cause of diseased action in it. All 

 these facts, however, point rather to the influence 

 which the nervous system possesses over the 

 organic functions, than to the dependence of 

 these upon its agency ; and it may be safely 

 asserted that no such proof of its more direct 

 influence, as is required to counterbalance the 

 manifest improbability which has been shown 

 to attend it, has yet been given. Some addi- 

 tional considerations upon this important sub- 

 ject will be offered under the head of SE- 

 CRETION. 



( W. B. Carpenter.) 



(ESOPHAGUS. (O'iu, I carry, and 

 I eat.) Gr. ou7o<payo<; ; Fr. cesophuge ; Ital. 

 gola; Germ. Speiserohre. The oesophagus is 

 that portion of the alimentary canal which 

 intervenes between the inferior extremity of the 

 pharynx and the cardiac orifice of the stomach. 

 It occupies the lower part of the cervical region, 

 traverses the thorax, and enters the abdomen. 



Direction. The direction of the oesophagus 

 is nearly vertical ; in the cervical region it 

 deviates slightly to the left ; in the upper part 

 of the thorax it inclines somewhat to the right, 

 and in the lower part of the same region it is 

 again directed to the left, so as to occupy the 

 median line during its passage through the 

 diaphragm. 



Dimensions. The oesophagus is not of uni- 

 form diameter throughout its entire length. 

 In the neck it is narrower than in any other 

 region ; it consequently happens that a morsel 

 of food too large to pass readily along the 

 O3sophagus, is usually arrestefl immediately 

 after it has been transmitted from the pharynx. 

 In its upper part the oesophagus is somewhat 

 flattened and compressed in the antero-pos- 

 tenor direction, but its inferior portion is more 

 or less cylindrical, and presents the appearance 

 of a rounded coi'd. 



Relations. The oesophagus has many im- 

 portant relations, which may be considered 

 successively in the cervical, thoracic, and ab- 

 dominal regions. In the cervical region it 

 corresponds anteriorly to the membranous part 

 of the trachea, with which it is connected by 

 some intervening cellular tissue : in the lower 

 part of the neck where it deviates to the left 

 it comes in contact anteriorly with the left 

 sterno-thyroid muscle, the thyroid gland, the 

 inferior thyroid artery, and the left recurrent 

 nerve. Posteriorly it has the cervical vertebrae 

 and the longus colli muscle, with which it is 

 connected by means of loose cellular tissue, so 

 that free movement of the oesophagus upon 

 the spine is allowed during the process of 

 deglutition. Laterally it is in relation with the 

 thyroid body, with the common carotid arteries, 

 and more externally with the vagi nerves and 

 the internal jugular veins. In consequence of 

 the oesophagus deviating slightly to the left in 

 the lower part of the neck, its relations are 

 somewhat different on the two sides. Thus the 

 left common carotid is in closer relation with 



the oesophagus than the right. The left recur- 

 rent nerve is anterior to the oesophagus, while 

 the right is somewhat posterior. 



The tlwrucic portion of the oesophagus is 

 placed in the posterior mediastinum. It cor- 

 responds anteriorly to the trachea, and imme- 

 diately below the bifurcation of the trachea to 

 the left bronchus, which crosses it obliquely, 

 to the arch of the aorta, to the left subclavian 

 and carotid arteries, and to the base of the heart, 

 from which it is separated by the pericardium. 

 Posteriorly it has the spine, with which in the 

 upper part of the chest it is in close contact ; 

 but as it descends it becomes separated from 

 the spine by cellular membrane, by the right 

 intercostal arteries, by the vena azygos, and by 

 the thoracic duct, which in the lower part of 

 the chest is on the right of the oesophagus, but 

 ascending it passes behind and above is placed 

 on its left side. At the inferior part of the 

 thorax, immediately before passing through the 

 diaphragm, the oesophagus has behind it the 

 thoracic aorta. Laterally it has on its left the 

 aorta, and on the right side the pleura forming 

 the right layer of the posterior mediastinum. 

 It is accompanied by the two vagi nerves, one 

 on each side, which send numerous filaments 

 from one to the other, and thus form the 

 plexus guise ; at the lower part of the chest the 

 left vagus nerve becomes somewhat anterior, 

 and the right posterior. This portion of the 

 oesophagus is surrounded by a considerable 

 quantity of loose cellular tissue and by several 

 lymphatic glands. 



The abdominal portion of the oesophagus is 

 very short, and has no relations of importance. 

 After passing through the diaphragm it is co- 

 vered both anteriorly and posteriorly by the 

 peritoneum. It also comes into contact ante- 

 riorly with the left lobe of the liver. Without 

 depressing the stomach and elevating the dia- 

 phragm this portion of the oesophagus cannot 

 be seen, and, in fact, can scarcely be said to 

 exist. 



Structure. The oesophagus is composed of 

 a muscular and a mucous coat, with some con- 

 necting cellular tissue. The muscular coat of 

 the oesophagus, which is considerably thicker 

 than that of any other portion of the alimen- 

 tary canal, consists of two distinct layers. The 

 external layer is composed of fibres arranged 

 in a longitudinal direction, and is twice the 

 thickness of the internal layer, the fibres of 

 which surround the canal in a circular man- 

 ner. The longitudinal fibres are regularly 

 disposed around the oesophagus ; superiorly 

 they arise in the median line from the pos- 

 terior surface of the cricoid caitilage, and 

 laterally on each side from the lower border 

 of the inferior constrictor muscle of the pha- 

 rynx ; at the inferior extremity of the oesopha- 

 gus they spread out and are continuous with 

 the longitudinal fibres of the stomach. The 

 circular fibres are a continuation of the pos- 

 terior part of the inferior constrictor muscle, 

 but they are much more delicate than the fibres 

 of this muscle. These fibres pass for the most 

 part transversely ; the spiral arrangement which 

 some anatomists have described does not ge- 



