The innervation of the bone marrow in laboratory animals

Abstract The nerve pattern of the bone marrow of the monkey, rabbit, rat and mouse was studied in serial sections specially stained to demonstrate myelinated and nonmyelinated nerve fibers. Features that are common to the different species studied were found in the bone marrow of the femur of the rat in a simple arrangement. A scheme is proposed based on thirteen photomicrographs demonstrating the nerve pattern of the bone marrow and the relation of the nerve fibers with the arterial tree, the sinusoids and the blood forming cells. This scheme shows that the necessary anatomical conditions exist permitting a direct influence of the nervous system on the function of the bone marrow. These conditions are the presence of myelinated nerve fibers traversing the parenchyma of the marrow, and the existence of nonmyelinated fibers ending in sphincterlike structures at the origin of the arterioles. Single myelinated nerve fibers and small bundles of both myelinated and nonmyelinated fibers lie in close contact with the endothelial wall of the sinuses during long trajects. Only the very thin endothelium of the sinuses separates the newly formed blood and the nerve fibers. An interaction between both elements is possible along these areas of contact.