Capsule of Lymph Node

The lymph node capsule is composed of dense irregular connective tissue with some plain muscle fibers, and from its internal surface are given off a number of membranous processes or trabeculæ, consisting, in man, of connective tissue, with a small admixture of plain muscle fibers; but in many of the lower animals composed almost entirely of involuntary muscle. They pass inward, radiating toward the center of the gland, for a certain distance—that is to say, for about one-third or one-fourth of the space between the circumference and the center of the gland. In some animals they are sufficiently well-marked to divide the peripheral or cortical portion of the gland into a number of compartments (so-called follicles), but in man this arrangement is not obvious. The larger trabeculæ springing from the capsule break up into finer bands, and these interlace to form a mesh-work in the central or medullary portion of the gland. In these spaces formed by the interlacing trabeculæ is contained the proper gland substance or lymphoid tissue. The gland pulp does not, however, completely fill the spaces, but leaves, between its outer margin and the enclosing trabeculæ, a channel or space of uniform width throughout. This is termed the lymph path or lymph sinus. Running across it are a number of finer trabeculæ of reticular connective tissue, the fibers of which are, for the most part, covered by ramifying cells.