Medullary cavity

The medullary cavity is the central cavity of bone shafts where red bone marrow and/or yellow bone marrow is stored; hence, the medullary cavity is also known as the marrow cavity.
Located in the main shaft of a long bone , the medullary cavity has walls composed of compact bone and is lined with a thin, vascular membrane.
Intramedullary is a medical term meaning the inside of a bone. Examples include intramedullary rods used to treat bone fractures in orthopedic surgery and intramedullary tumors occurring in some forms of cancer or benign tumors such as an enchondroma.

Comparative anatomy

This area is involved in the formation of red blood cells and white blood cells,
In some dinosaurs, reptiles, and birds, a medullary bone grows here, which supplies the calcium supply for eggshells. This has been detected in fossil bones despite the fossilization process. It is not found in crocodiles or reptiles.