Quick Facts
A lymphatic vessel is a vessel that collects lymph from the tissues and through which the lymph passes to reach the bloodstream (Dorland, 2011).
Structure/Morphology
The skin contains a rich network of lymph vessels in the dermis and hypodermis; the epidermis contains no lymph vessels.
The lymph capillaries in the skin, otherwise known as the initial lymph vessels, create a network in the superficial layers of the skin which is referred to as the subpapillary cutaneous network. A deep group of lymphatic afferent vessels that arise at the dermal papillae converge forming the deep cutaneous plexus in close proximity to the blood vessels in the reticular layer (Földi et al., 2012).
A much denser cutaneous lymphatic network is seen in areas of skin in which there are ridges on the surface, an example being the fingers, as opposed to areas of skin with a flatter surface.
Recent studies have suggested that the tissue arrangement of dermis is not a densely packed wall-like structure, commonly seen in alcohol fixed tissue. In fact, it is composed of a collagen lattice surrounded by fluid filled interstitial spaces, the interstitium (Benias et al., 2018). The fluid has been described as pre-lymph where it is collected by lymph capillaries to form lymph. This has also been described in other tissues, such as lung, renal, blood vessel adventitia, and fascia.
Function
The lymph vessels function as a drainage system of the interstitial fluid which has ‘leaked’ from capillary networks, converting it to lymph. From this point they transport the lymph through the lymphatic system and return it to the venous system.
References
Benias, P. C., Wells, R. G., Sackey-Aboagye, B., Klavan, H., Reidy, J., Buonocore, D., Miranda, M., Kornacki, S., Wayne, M., Carr-Locke, D. L. and Theise, N. D. (2018) 'Structure and Distribution of an Unrecognized Interstitium in Human Tissues', Scientific Reports, 8(1), pp. 4947.
Dorland, W. (2011) Dorland's Illustrated Medical Dictionary. 32nd edn. Philadelphia, USA: Elsevier Saunders.
Földi, M., Földi, E., Strößenreuther, R. and Kubik, S. (2012) Földi's Textbook of Lymphology: for Physicians and Lymphedema Therapists. Elsevier Health Sciences.
