The =pancreas= is situated transversely on the dorsal wall of the
abdomen, the greater part being to the right of the median plane. Its
central part lies under the sixteenth and seventeenth thoracic vertebræ.
When fresh it has a reddish cream color, but if left in the unpreserved
cadaver it rapidly decomposes and becomes dark. It resembles the
salivary glands in appearance, but is softer, and its lobules are more
loosely united. Its average weight is about twelve ounces (ca. 350 g.).
When hardened in situ its shape is very irregular. It is triangular in
outline, and presents for description two surfaces, three borders, and
three angles.[97]
The =dorsal surface= faces upward and forward. It is partially covered
by peritoneum. It is related chiefly to the ventral surface of the right
kidney and adrenal, the posterior vena cava, the portal vein, the cœliac
artery and its divisions, the gastro-phrenic ligament and the saccus
cæcus of the stomach, the right and caudate lobes of the liver, and the
gastro-pancreatic fold. There are grooves for the divisions of the
cœliac artery, and a large one for the splenic vein.
The =ventral surface= looks downward and backward; it is in general
concave. It presents two impressions, separated by an oblique ridge. The
smaller of these (Impressio cæcalis) lies to the right, and is caused by
the pressure of the base of the cæcum; the larger one (Impressio colica)
indicates the area of contact with the terminal part of the great colon
and its junction with the small colon. It has usually no peritoneal
covering except over a small area at the anterior angle.
The =right border= is nearly straight; it is related to the second part
of the duodenum and the caudate lobe of the liver.
The =left border= is slightly concave, and is related to the first part
of the duodenum, the left sac of the stomach, and the splenic vessels.
The =posterior border= presents a deep notch to the right of the median
plane for the portal vein, which passes through the gland very
obliquely. There is a thin bridge of gland tissue dorsal to the vein,
thus forming the =portal ring= (Annulus portarum). The root of the great
mesentery is in contact with the border just to the left of the median
plane.
The =anterior= or =duodenal angle= (Caput pancreatis) is attached to the
concavity of the second curve of the duodenum, and the adjacent part of
the right lobe of the liver. The ducts leave at this extremity.
The =left= or =splenic angle= (Cauda pancreatis) corresponds to the tail
of the pancreas in man. It is in contact with the base of the spleen,
the left kidney and adrenal body, and the saccus cæcus of the stomach.
[Illustration: