Articles

Studies on the Lymph Node-Venous Communications III. The Presence of Saccular Sinuses and their Possible Function

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Abstract

From analysis of serial sections of the canine medial retropharyngeal lymph node, sinuses with a saccular configuration have been delineated. Maximum dimensions of the saccular sinus analyzed varied from 13-25 μ through the depth of the serial sections, a distance of approximately 0.5 mm. The saccular sinus opened at either end into a normal, irregularly-shaped sinus. Continuity was observed between a distinctly separate tubular vessel and the saccular sinus. The vessel appears to arise obliquely from the saccular sinus and is first seen as an evagination, approximately 100 μ in length, of the endothelial border of the saccular sinus. At the region of continuity, the vessel was approximately 10 μ in diameter and increased to approximately 25 μ in diameter where fully separated from the saccular sinus. Approximately 20 μ from the region of vessel-saccular sinus continuity, endothelial strands projected across the vessel lumen. Reconstructions of approximately 36 μ of this area disclosed that these strands were tricuspid and arch-shaped in structure and could function as a valve. These structw:es are discussed in relationship to the direct lymph node-venous transfer of tracer substances.

When the lymphatic duct becomes obstructed as a result of either induced or pathological obstacles, functional extranodal lymphaticovenous communications appear to act as a bypass mechanism (1-8). Experimental evidence has demonstrated the presence of lymph node-venous communications, has shown that short-term, rapid passage of tracer substances and cells may be pressure related, and has suggested that certain anatomical structures may serve as a mixing chamber with two possible exits (9, 10). Histological evidence is presented herein to document the presence of a system of anatomical structures which may serve as the morphological pathway for intranodal pressurerelated transfer from lymph node sinuses directly to the venous system.

How to Cite:

Dunn, R. & Strahan, R., (1972) “Studies on the Lymph Node-Venous Communications III. The Presence of Saccular Sinuses and their Possible Function”, Lymphology 5(4), 161-169.