lymph vessel
Meaning of lymph vessel: The plumbing that fails in lymphedema and the route many cancers travel out of an organ, known equally as a lymphatic vessel.
Definition of lymph vessel
A lymph vessel is any of the thin tubes that collect lymph from the tissues and carry it toward the base of the neck, where it empties into large veins. Along the way the fluid passes through lymph nodes, which filter it and present its contents to immune cells. The wall is thinner than that of a vein of similar size and holds frequent one-way valves.
What are the main types?
They are named by size and by the job each does on the route back to the blood. The term is interchangeable with lymphatic vessel.
| Type | What it does |
|---|---|
| Lymphatic capillary | Blind-ended, admits fluid and particles from the tissue |
| Collecting vessel | Valved and muscular, pushes lymph along in segments |
| Trunk | Gathers drainage from a whole region such as a limb |
| Duct | Empties into the veins at the base of the neck |
What happens when one is blocked?
Fluid backs up into the tissue and stays there, producing the firm, pitting-then-hardening swelling called lymphedema. Because the trapped fluid is rich in protein, it draws in more water and provokes scarring, so long-standing swelling thickens the skin and does not resolve with elevation alone. Damage from surgery, radiation or repeated infection is the usual cause in wealthier countries. Worldwide the commonest cause is filariasis, in which thread-like parasitic worms lodge in the vessels themselves. Stagnant protein-rich fluid also predisposes the limb to repeated skin infection, and each episode damages more vessels.
Why do cancers travel along them?
The wall of a lymphatic capillary is a poor barrier by design, so a tumor cell that reaches one enters easily and is carried passively to the first node downstream. A pathologist who sees tumor cells inside these channels reports lymphovascular invasion, a finding that raises the estimated risk of spread. The predictable order of lymph node drainage is what makes it possible to test the first node on the path and infer the state of the rest, and it is why the pattern of swollen nodes points back toward where a problem started.
Also known as
Used in a sentence
The dissection was carried out with care to avoid injury to the lymph vessels of the groin.
Good to know
Lymphedema from damaged or removed vessels is generally permanent, because lost drainage channels do not regrow, and the protein-rich fluid that collects promotes scarring and repeated skin infection.