Embryology and clinical importance of lymph nodes

1. Embryology and clinical
importance of lymph nodes
Harsha Kumar M S
#39

2. Embryology of lymph nodes
 The first signs of lymphatic system are
seen in the form of a number of
endothelium lined lymph sacs.
 These sacs out growth from veins.
 However ,they are now regarded to be
predominantly independent formation
from mesenchyme.
 Six sacs can be recognised .

3. • The right and left jugular sacs lie near the junction of post
cardinal and subclavian veins
•The right and left post ileac sacs lie aroumd the
corresponding common ileac vein
•The retro-peritonial sac lies in relation to the route of the
mesentry
•The 6th sac is the cisterna chyli lies in the mid line , some
distance caudal to the retro peritoneal sacs
•Lymphatic vessels are formed either by extension from
the sacs or may form de novo and extend into various
tissues
•Ultimately all the sacs except the cysterna chyli are
invaded by connective tissue and lymphocytes and are
converted into group of lymph nodes

5. Clinical importance of lymph
nodes
 Lymph nodes enlarges due to infections,
tumors or inflamed due to leukemia
 Increased size is primarily due to trafficking
of lymphocyte into the node from the blood
exceeding the rate of outflow from the neck
 Secondarily as a result of activation and
proliferation of antigen specific B and T
cells(clonal expansion)

8. THANK YOU