Observations on the innervation of human long bones

The innervation of some of the long bones of the extremities of the human was studied by methylene blue immersion. Small myelinated and amyelinated nerve fibers enter the numerous foramina of the epiphyseal and metaphyseal regions of long bones, traverse the thin cortex, and supply the interior of the bone. Small myelinated fibers wind about the trabeculae of the spongiosa or spread out on the undersurface of the articular cartilage. Small knob‐like terminations end in close relationship to the endosteum. Other myelinated nerve fibers have branched free fiber endings associated with the walls of intertrabecular marrow arterioles. Amyelinated nerve fibers are usually associated with vascular walls but may also be associated with the connective tissue of the intertrabecular fat or marrow. Numerous myelinated and amyelinated nerve fibers traverse the nutrient foramen and supply the bone marrow and endosteum of the shaft of the bone. While the Volkmann's canals of the shaft receive nerve fibers from the overlying periosteum, the disposition of these fibers in the shaft of the bone has not been determined. No nerve fibers or endings were ever seen between the lamellae in any location. No function can yet be attributed to any particular type of nerve fiber or nerve ending.