The =cisterna chyli= is large and fusiform. The =thoracic duct= may be
single throughout, but often divides anteriorly into two branches, which
may then unite and form a dilatation which receives the left tracheal
duct and the vessels from the fore limb. The primitive plexiform
arrangement persists in varying degree. The duct terminates in the left
brachiocephalic vein.
The =tracheal ducts= accompany the internal jugular veins. The right
duct opens into the right brachiocephalic vein.
The =submaxillary lymph glands= (Fig. 486) are commonly three in number
on each side. They are situated in the angle between the masseter and
the submaxillary salivary gland, in relation to the external maxillary
vein and covered only by the skin and panniculus. The number may be
reduced to two or one with a corresponding increase in size.
A small round =parotid= or =auricular lymph gland= is situated
superficially between the upper part of the posterior border of the
masseter and the parotid gland.
The =pharyngeal= (or retropharyngeal) =lymph glands=, one or two in
number on each side, lie on the pharynx chiefly under cover of the
submaxillary salivary gland.
The =prescapular= or =superficial cervical lymph glands= lie on the
serratus magnus at the anterior border of the supraspinatus, embedded in
a mass of fat. Usually two or three are present on each side, but there
may be only one. They are oval and are about an inch long in a dog of
medium size when two are present.
The =axillary lymph gland= lies in a mass of fat on the inner face of
the lower part of the teres major. It is discoid.
The =cubital lymph gland= is inconstant. It is situated on the deep face
of the long head of the triceps or on the latissimus dorsi.
The =mediastinal lymph glands= are small and quite variable in
arrangement. Usually one or two glands are found on the course of the
internal thoracic vessels at the second segment of the sternum.
The =bronchial lymph glands= are commonly four in number. The largest is
situated in the angle of divergence of the chief bronchi, two lie on the
origin of the right apical bronchus, and the fourth is between the
aortic arch and the anterior face of the left bronchus. They are
commonly pigmented.
The =lumbar lymph glands= are small.
The =mesenteric lymph glands= are represented chiefly by a long
flattened mass (formerly known as the pancreas Aselli) which lies in the
mesentery along the course of the anterior mesenteric artery and vein.
It is succeeded by three or four glands which lie along the portal vein
and appear to receive vessels from the stomach, spleen, liver, pancreas,
and great omentum. A few very small nodes occur along the colon.
The =iliac lymph glands= are relatively large and are situated at the
termination of the aorta and the origin of the iliac arteries. Commonly
four are present. Of these, the two largest lie on the psoas minor on
each side in relation to the aorta and vena cava respectively. The other
two are in the angle of divergence of the internal iliac arteries.
The =superficial inguinal lymph glands= are situated in the subcutaneous
fat behind the external inguinal ring. They are relatively large,
especially when there is only one on each side; two smaller ones may be
found instead.
The =popliteal lymph gland=—usually unique, but sometimes double—lies in
a pad of fat on the upper part of the gastrocnemius between the biceps
femoris and semitendinosus. It may project back so as to be superficial
and palpable.