Agriculture Reference
In-Depth Information
node lying midway between these and 15 cm deep.
D:
Lower part of the leg and foot.
E:
Lumbar and iliac nodes
and also ischiatic node.
may be left on the inner side of the jaw after the head is
removed.
Prescapular (superficial cervical)
On account of the short neck of the pig, these nodes lie
close to the parotid salivary gland, being partly covered
by its posterior border. They form an oblique chain
which is directed downwards and backwards to the
shoulder joint. This chain really includes all the super-
ficial cervical nodes and is best exposed by a long inci-
sion, made on the inside of the carcase, from the nape
of the neck to the lower border of the neck and just
anterior to the shoulder joint. The prescapular lymph
nodes in the pig receive lymph from the submaxillary,
parotid and upper cervical nodes and thus may become
tuberculous as a result of primary infection of the
lymph nodes of the head. Enlargement of the prepecto-
ral node in pigs may occur as a result of arthritic
changes in the forelimbs.
Lymph nodes of the pig (Fig. 2.13)
Head and neck
The nodes of the head and neck are numerous and some-
what difficult to group satisfactorily. They include the
following.
Submaxillary (mandibular)
These lie anterior to the submaxillary salivary gland near
to the angle of the jaw and are covered by the lower part
of the parotid salivary gland. There are commonly two
nodes on each side, one large and one small.
Anterior or upper cervical
Known also as the accessory submaxillary or subman-
dibular, these lie a short distance behind and above the
preceding nodes, being separated from them by the
submaxillary salivary gland.
Other nodes
Precrural (sub-iliac)
In adult pigs, this is up to 5 cm in length and 2.5 cm in
width and is most easily exposed by an incision through
the peritoneal aspect of the carcase deep into the fat and
2.5 cm in front of the stifle joint, the incision being made
at right angles to the vertebral column.
Parotid
There are several nodes on each side, which are red in
colour, one of the largest being situated just posterior
to the masseter muscle of the lower jaw and partly cov-
ered by the parotid salivary gland. One or two nodes
Popliteal
When present, these are superficial but are absent in 50%
of cases. A small subcutaneous node, known as the hock
node or Hartenstein's gland, can constantly be found and
is superficially placed on the posterior aspect of the limb
about a hand's breadth above the tuber calcis.
g
f
e
Gastric
These and the pancreatic nodes are situated on the lesser
curvature of the stomach.
h
i
j
Bronchial
In addition to the right and left bronchial, this group
includes one on the bifurcation of the trachea and
another at the apical bronchus of the right lung. The pos-
terior mediastinal nodes are rudimentary or absent.
d
c
Portal
Several nodes are present about the portal vein, the larg-
est being about 2.5 cm long. The portal lymph nodes
may be removed during evisceration of the carcase and
can then be found on the mesentery beneath the pan-
creas or in the fat attached to the lesser curvature of the
stomach.
a
b
Figure 2.13
Side of pork showing position of lymph nodes:
a, submaxillary; b, anterior or upper cervical; c, prepectoral;
d, presternal; e, precrural; f, superficial inguinal; g, hock node;
h, iliac; i, lumbar; j, renal.
