332 THE CIRCULATORY SYSTEM. 
gland situated close to the caudoventral surface of the tympanic 
bulla, at the side of the pharynx. Thence a large lymphatic 
trunk passes caudad at the side of the trachea, along with the 
common carotid artery and internal jugular vein, unites with 
the superficial vessels from the head, above described, joins 
(on the left side) the thoracic duct, and enters the external 
jugular vein. 
2. Lymphatics of the Neck.—Two or three lymph-glands 
are found in the fatty mass in the neck beneath the clavotrape- 
zius and levator scapule ventralis muscles. These receive 
lymphatics from the neck and side of the thorax. The vessels 
which arise from them join those from the head and arm to 
enter the external jugular vein. 
3. Lymphatics of the Thoracic Limbs.—The lymphatics 
of the forelimbs begin as a number of vessels on the dorsum 
and palm of the hand. These all pass toward the radial side, 
and at about the base of the first metacarpal the vessels from 
both sides of the hand unite to form two or three main trunks. 
These pass towards the elbow, accompanying the vena cepha- 
lica (Fig. 130). There are usually two of these main trunks, 
one lying on each side of the vena cephalica. They accompany 
this vein over the shoulder, following that portion which finally 
joins the external jugular. In the hollow of the shoulder they 
enter the cervical lymph-glands, one or two lymph-glands 
imbedded in the fat lying beneath the clavotrapezius and 
levator scapule ventralis in this region. From the cervical 
lymph-glands a single trunk passes mediocaudad, unites with 
the lymphatics from the head, and usually (on the left side) 
with the cranial end of the thoracic duct, and enters the 
external jugular vein at its junction with the subclavian. The 
common trunk from the head and arm may enter the jugular 
separately, but close to the termination of the thoracic duct. 
On the right side the common trunk is joined by one or more 
small vessels coming from the lymphatic glands of the thorax 
and forming the right lymphatic duct. 
There is said to be also a deep system of lymphatics in the 
arm, in addition to the superficial system above described; this 
is said to accompany the branches of the brachial vein. If this 
