drains portions of the neck and head. These
lymphatic trunks then join one of two
thoracic duct or the right lymphatic duct.
the location of the major lymphatic trunks and collecting
f gure 16.5
shows a lymphangiogram, or radio-
graph, of some lymphatic vessels and lymph nodes.
is the larger and longer of the two col-
lecting ducts. It originates in the abdomen, passes upward
through the diaphragm beside the aorta, ascends anterior to
the vertebral column through the mediastinum, and empties
into the left subclavian vein near the junction of the left jugu-
lar vein. This duct drains lymph from the intestinal, lumbar,
and intercostal trunks, as well as from the left subclavian,
left jugular, and left bronchomediastinal trunks.
right lymphatic duct
originates in the right thorax
at the union of the right jugular, right subclavian, and right
bronchomediastinal trunks. It empties into the right subcla-
vian vein near the junction of the right jugular vein.
Lymph leaves the two collecting ducts, then enters the
venous system and becomes part of the plasma prior to the
Schematic representation of lymphatic vessels
uid from interstitial spaces to the bloodstream.
Lymphatic capillaries are microscopic, closed-ended
tubes that originate in the interstitial spaces of most tissues.
Light micrograph of the F
aplike valve (arrows) within
a lymphatic vessel (60×).