Abdominal
pain
Abdominal pain arising from the alimentary
canal is of two types.
1.
Visceral pain. The alimentary tract is primarily a midline structure with
a bilateral nerve supply. Although rotation about the midline occurs during
development, nevertheless true visceral pain is referred to the midline as shown
in Fig. 57.1. It is dull and poorly localised. For example, an obstructing
stenosis of the terminal ileum, which is part of the midgut, would give rise to
colicky periumbilical pain.
2.
Peritoneal pain is of the somatic type and is much more precise, more
severe and localised to the site of origin. These components account for the
changes in character and site of pain which occur in appendicitis. Once the
full thickness of the appendicular wall becomes inflamed the overlying
peritoneum becomes involved and the patient has localised right iliac fossa pain
(see Chapter 59).
Surgical
anatomy
It is of great practical importance to be able
to do the following:
1.distinguish
various portions of the intestinal tract at sight;
2.know
in which part of the abdomen the upper coils, as opposed to the lower coils, of
small intestine lie in relationship to the anterior abdominal wall;
3.be
able to decide which is the proximal and which is the distal end of any coil
under consideration;
4.
distinguish irrefutably large from small intestine.
• The mesentery of the jeiunum has only two series of arcades of blood
vessels, whereas the lower ileum has several series of arcades.
• The mesenteric attachment runs from left to right. Provided that the
gut is not twisted, the proximal small bowel lies in the upper part of the
abdomen and the lower small bowel lies in the lower part of the abdomen.
• The large intestine can be characterised by its taenia coli and
appendices epiploicae.