758 
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 as 
to become a cause of diseased action in it. All 
these facts, however, point rather to the influence 
which the nervous system s 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.) 
CESOPHAGUS. (Ofw, I carry, and dayw, 
I eat.)\—Gr. oicoPayos; Fr. esophage; Ital. 
gola; Germ. Speiserdhre. The cesophagus is 
that portion of the alimentary canal which 
intervenes between the inferior extremity of the 
pharynx and the cardiac orifice of the stomach. 
t occupies the lower part of the cervical region, 
traverses the thorax, and enters the abdomen. 
Direction.—The direction of the esophagus 
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. 
imensions.—The cesophagus 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 
esophagus, is usually arrested immediately 
after it has been transmitted from the pharynx. 
In its upper part the esophagus is somewhat 
flattened and compressed in the antero-pos- 
terior direction, but its inferior portion is more 
or less cylindrical, and presents the appearance 
of a rounded cord. 
Relations.—The cesophagus 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 
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, aud the left recurrent 
nerve. Posteriorly it has the cervical vertebra 
and the longus colli muscle, with which it is 
connected by means of loose cellular tissue, so 
that free movement of the csophagus 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 @sophagus deviating slightly to the left in 
the lower of the neck, its relations are 
somewhat different on the two sides. Thus the 
left common carotid is in closer relation with 
(ZSOPHAGUS. 
, es - 
the esophagus than the right. The left recur- 
rent nerve is anterior to the cesophagus, while — 
the right is somewhat posterior. “ 
The thoracic portion of the cesophagus is — 
placed in the posterior mediastinum. It cor 
responds anteriorly to the trachea, aad imme- 
diately below the bifurcation of the trachea to- 
the left bronchus, which crosses it obliquel, 
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 bi 
the thoracic duct, which in the lower part 
the chest is on the right of the esophagus, ba 
ascending it passes behind and above is plac 
= its left side. At the inferior _ 
thorax, immediately before passi rough the 
diaphragm, the cceophoget has aa it the 
thoracic aorta. Laterally it has on its left 
aorta, and on the right side the pleura forn 
the right layer of the posterior mediastinam 
It is accompanied by the two vagi nerves, © 
on each side, which send numerous filamen 
from one to the other, and thas form — 
lexus gule ; at the lower part of the chest # 
eft vagus nerve becomes somewhat anter 
and the right posterior. This portion of 1 
cesophagus is surrounded by a considera 
quantity of loose cellular tissue and by seve 
vee glands. 
The abdominal portion of the esophagus 
very short, and has no relations of impo’ 
€ 
‘4 
After ing through the diaphragm it is ¢ 
vered both anteriorly and posteriorly -by 
peritoneum. It also comes into contact al 
riorly with the left lobe of the liver. With 
depressing the stomach and elevating th 2 
aa this portion of the a 
e seen, and, in fact, can scarcely 
exist. 
Structure —The cesophagus is composet 
a muscular and a mucous coat, with some 
necting cellular tissue. The muscular 
the esophagus, which is considerably th 
than that of any other portion of the alli 
tary canal, consists of two distinct layers. 
external layer is composed of fibres arra 
in a longitudinal direction, and is twice 
thickness of the internal layer, the 
which surround the canal in a cireula 
ner. The longitudinal fibres are re 
disposed around the esophagus; sup 
they arise in the median line from th 
terior surface of the cricoid cartilage 
laterally on each side from the le 
of the inferior constrictor muscle of 
rynx; at the inferior extremity of the @ 
gus they spread out and are continuo! 
the longitudinal fibres of the stomac 
circular fibres are a continuation of th 
terior part of the inferior constrictor m 
but they are much more delicate than the 
of this muscle. These fibres pass for th 
part transversely ; the spiral arrangement 
some anatomists have described de 
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