It’s essential for bones to be connected to the circulatory system, but little is known about how circulation works in that part of the body. Scientists do know that if a drug is injected into a bone, the drug quickly exits the bone, and can rapidly get to other areas of the body.
Scientists in Germany have learned more about circulation in bones by rendering bones transparent. That enabled them to reveal a small network of capillaries they have named ‘trans-cortical vessels.’ Immune cells are made in bone marrow, and this network moves them out of bone and into circulation. Learn more from the video by Nature.
Source: Nature Metabolism