Subcapsular sinus
Encyclopedia
The subcapsular sinus is a region within the lymph node
immediately deep to the capsule that contains relatively sparse lymphocyte
s. It thus allows lymph
to flow freely through it.
The lymph node contains lymphoid tissue, i.e., a meshwork or fibers called reticulum with white blood cell
s enmeshed in it. The regions where there are few cells within the meshwork are known lymph sinus. It is lined by reticular cells, fibroblast
s and fixed macrophage
s.
Thus, subcapsular (sub=below) sinus lies immediately deep to the capsule of the lymph node and immediately above the cortex. It is continuous with the similar lymph sinuses that flank the trabeculae (the extensions of capsule within the substance of the lymph node).
The subcapsular sinus is of clinical importance as it is the most likely location where the earliest manifestations of a metastatic carcinoma in a lymph node would be found.
Lymph node
A lymph node is a small ball or an oval-shaped organ of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as...
immediately deep to the capsule that contains relatively sparse lymphocyte
Lymphocyte
A lymphocyte is a type of white blood cell in the vertebrate immune system.Under the microscope, lymphocytes can be divided into large lymphocytes and small lymphocytes. Large granular lymphocytes include natural killer cells...
s. It thus allows lymph
Lymph
Lymph is considered a part of the interstitial fluid, the fluid which lies in the interstices of all body tissues. Interstitial fluid becomes lymph when it enters a lymph capillary...
to flow freely through it.
The lymph node contains lymphoid tissue, i.e., a meshwork or fibers called reticulum with white blood cell
White blood cell
White blood cells, or leukocytes , are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...
s enmeshed in it. The regions where there are few cells within the meshwork are known lymph sinus. It is lined by reticular cells, fibroblast
Fibroblast
A fibroblast is a type of cell that synthesizes the extracellular matrix and collagen, the structural framework for animal tissues, and plays a critical role in wound healing...
s and fixed macrophage
Macrophage
Macrophages are cells produced by the differentiation of monocytes in tissues. Human macrophages are about in diameter. Monocytes and macrophages are phagocytes. Macrophages function in both non-specific defense as well as help initiate specific defense mechanisms of vertebrate animals...
s.
Thus, subcapsular (sub=below) sinus lies immediately deep to the capsule of the lymph node and immediately above the cortex. It is continuous with the similar lymph sinuses that flank the trabeculae (the extensions of capsule within the substance of the lymph node).
The subcapsular sinus is of clinical importance as it is the most likely location where the earliest manifestations of a metastatic carcinoma in a lymph node would be found.