Isaac Schour Memorial Award for Research and Teaching in Anatomical Sciences

¹ School of Dentistry, Loycla University, Chicago, Illinois

The loose connective tissue is most often decribed as "packing blood vessels and nerves, as "intervening" between muscles, as "binding" skin or mucous membranes to underlying structures. Two of its characteristics are often forgotten: its ubiquitousness, that is, its presence in dense connective tissue, or in compact bone, surrounding vessels and nerves in the former, haversian blood vessels in the latter; and its containing the least differentiated mesodermal cell, the undifferentiated mesenchymal cell of Maximow, better termed the reserve cell of the connective tissue. It is this pluripotential cell that gives to the loose connective tissue its great significance in wound healing as the organ of repair. Soft tissues, as well as bones are dependent in healing, repair, and regeneration on the proliferation of the reserve cells and their differentiation into fibroblasts, chondroblasts, osteoclasts, or osteoblasts. This function is already active in the development of endochondral bone where the cartilage of the "model" is invaded and replaced by mesenchyme, the ancestral tissue of loose connective tissue, and in the physiologic internal reconstruction of compact bone where the resorbed bone is replaced by proliferating loose connective tissue, the undifferentiated mesenchymal cells of which differentiate into osteoblasts. It can be said that the loose connective tissue is the direct derivative of the fetal mesenchyme persisting throughout life.