Page 89 - Clinical Anatomy

ECA2 7/18/06 6:42 PM Page 74

74 The abdomen and pelvis

vagus supplies branches to the cardia and lesser curve of the stomach and
also a large hepatic branch. The posterior vagus gives branches to both the
anterior and posterior aspects of the body of the stomach but the bulk of
the nerve forms the coeliac branch. This runs along the left gastric artery to
the coeliac ganglion for distribution to the intestine, as far as the midtrans-
verse colon, and the pancreas.
The exact means by which the vagal fibres reach the stomach is of con-
siderable practical importance to the surgeon. The gastric divisions of both
the anterior and posterior vagi reach the stomach at the cardia and descend
along the lesser curvature between the anterior and posterior peritoneal
attachments of the lesser omentum (the anterior and posterior nerves of
Latarjet). The stomach is innervated by terminal branches from the anterior
and posterior gastric nerves and it is, therefore, possible to divide those
branches which supply the acid-secreting body of the stomach yet preserv-
ing the pyloric innervation (highly selective vagotomy, see below).
The vagus constitutes the motor and secretory nerve supply for the
stomach. When divided, in the operation of vagotomy, the neurogenic
(reflex) gastric acid secretion is abolished but the stomach is, at the same
time, rendered atonic so that it empties only with difficulty; because of this,
total vagotomy must always be accompanied by some sort of drainage pro-
cedure, either a pyloroplasty (to enlarge the pyloric exit and render the
pyloric sphincter incompetent) or by a gastrojejunostomy (to drain the
stomach into the proximal small intestine). Drainage can be avoided if
the nerve of Latarjet is preserved, thus maintaining the innervation and
function of the pyloric antrum (highly selective vagotomy).

Clinical features

1◊◊A posterior gastric ulcer or cancer may erode the pancreas, giving pain
referred to the back. Ulceration into the splenic artery — a direct posterior
relation—may cause torrential haemorrhage.
2◊◊There may be adhesions across the lesser sac which bring the transverse
mesocolon into intimate relationship with the stomach or greater omen-
tum. In these circumstances the middle colic vessels are in danger of
damage during mobilization of the stomach for gastrectomy.
3◊◊Radiology of the stomach (Fig. 56). A plain erect film of the abdomen
reveals a bubble of air below the left diaphragm; this is gas in the stomach
fundus. After the subject has swallowed radio-opaque contrast fluid, for
example barium sulphate, the stomach can be seen and its position, move-
ments and outline studied. The wide variations in the position and shape of
the stomach that we have already mentioned have come to light principally
as a result of such investigations.
By tipping the subject head-down, the opaque meal can be made to
impinge against the cardia; incompetence of this sphincter mechanism will
be demonstrated by seeing barium regurgitate into the oesophagus.
4◊◊Gastroscopy. The mucosa of the air-inflated stomach can be inspected in
the living subject through the gastroscope. With the modern fibre-optic