Quick Facts
The capsule is the outer layer of a lymph node, composed mainly of collagen fibers with a few fibroblasts and elastin fibers (Dorland, 2011).
Structure/Morphology
Each lymph node is surrounded by a tough capsule of dense irregular connective tissue. The capsule is composed mainly of collagen and elastin fibers, with some fibroblasts interspersed. Smooth muscle is also present in the capsule of lymph nodes, especially those found in the axillary and inguinal regions (Ohtani and Ohtani, 2012). This smooth muscle is thought to be involved in the expulsion of lymph and lymphocytes into the efferent vessel of the lymph node.
Anatomical Relations
The capsule surrounds and supports the lobules of the lymph node and separated from it by the subcapsular sinus.
Function
Trabeculae extend from the capsule into the cortex of the lymph node to provide support within the node.
References
Dorland, W. (2011) Dorland's Illustrated Medical Dictionary. 32nd edn. Philadelphia, USA: Elsevier Saunders.
Ohtani, O. and Ohtani, Y. (2012) 'Recent Developments in Morphology of Lymphatic Vessels and Lymph Nodes', Annals of Vascular Diseases, 5(2), pp. 145-150.
