Innervation of the vessels of the marrow cavity of certain bones

Abstract

The vasoconstrictor fibers passing to the marrow cavities of certain bones have been traced by cutting specific nerves and stimulating their peripheral ends. A reduction in marrow pressure signifies vasoconstriction. The tibia is supplied with vasoconstrictor fibers arising from the lumbar spinal cord and running mainly in the sciatic and tibial nerves. Vasoconstrictor fibers emerging from the lumbar region reach the femur by way of the femoral nerve and its branches. The humerus receives vasoconstrictor fibers from the upper thoracic segments. These are carried mainly in the median nerve. Vasoconstrictor fibers arising from T₂, synapse in two-thirds of the cats in the stellate ganglion, pass up the cervical sympathetic chain and along the external carotid artery and its branches to reach the mandible. In one-third of the animals studied the synapses are located in the superior cervical ganglion.