Supraclavicular lymph nodes
Supraclavicular lymph nodes are lymph nodes found above the clavicle, that can be felt in the supraclavicular fossa. The supraclavicular lymph nodes on the left side are called Virchows nodes. It leads to an appreciable mass that can be recognized clinically, called Troisier sign.

Structure
A Virchows node is a left-sided supraclavicular lymph node.

Clinical significance
Malignancies of the internal organs can reach an advanced stage before giving symptoms. Stomach cancer, for example, can remain asymptomatic while metastasizing. One of the first visible spots where these tumors metastasize is one of the left supraclavicular lymph node.
Virchows nodes take their supply from lymph vessels in the abdominal cavity, and are therefore sentinel lymph nodes of cancer in the abdomen, particularly gastric cancer, ovarian cancer, testicular cancer and kidney cancer, that has spread through the lymph vessels, and Hodgkins lymphoma. Such spread typically results in Troisiers sign, which is the finding of an enlarged, hard Virchows node.The left supraclavicular nodes are the classical Virchows node because they receive lymphatic drainage of most of the body (from the thoracic duct) and enters the venous circulation via the left subclavian vein. The metastasis may block the thoracic duct leading to regurgitation into the surrounding Virchows nodes. Another concept is that one of the supraclavicular nodes corresponds to the end node along the thoracic duct and hence the enlargement.Differential diagnosis of an enlarged Virchows node includes lymphoma, various intra-abdominal malignancies, breast cancer, and infection (e.g. of the arm).  Similarly, an enlarged right supraclavicular lymph node tends to drain thoracic malignancies such as lung and esophageal cancer, as well as Hodgkins lymphoma.

History
Virchows nodes are named after Rudolf Virchow (1821–1902), the German pathologist who first described the nodes and their association with gastric cancer in 1848. The French pathologist Charles Emile Troisier noted in 1889 that other abdominal cancers, too, could spread to the nodes.

Additional images
References
This article incorporates text in the public domain from page 697 of the 20th edition of Grays Anatomy (1918)

Further reading
Cervin, J. R.; Silverman, J. F.; Loggie, B. W.; Geisinger, K. R. (1995). "Virchows node revisited. Analysis with clinicopathologic correlation of 152 fine-needle aspiration biopsies of supraclavicular lymph nodes". Archives of Pathology & Laboratory Medicine. 119 (8): 727–30. PMID 7646330. INIST:3670181 NAID 10026546830.
Negus, D; Edwards, J M; Kinmonth, J B (7 December 2005). "Filling of cervical and mediastinal nodes from the thoracic duct and the physiology of virchows node—studies by lymphography". British Journal of Surgery. 57 (4): 267–271. doi:10.1002/bjs.1800570407. PMID 5437920. S2CID 19698597.
Mizutani, Masaomi; Nawata, Shin-ichi; Hirai, Ichiro; Murakami, Gen; Kimura, Wataru (December 2005). "Anatomy and histology of Virchows node". Anatomical Science International. 80 (4): 193–198. doi:10.1111/j.1447-073x.2005.00114.x. PMID 16333915. S2CID 40130186.

External links
synd/1222 at Who Named It?
Image at umich.edu - must rollover
https://web.archive.org/web/20080216031919/http://www.med.mun.ca/anatomyts/head/hnl3a.htm
http://www.aafp.org/afp/20021201/2103.html