Blood production —The marrow, located within the medullary cavity of long bones and the interstices of cancellous bone, produces blood cells in a process called haematopoiesis.
This ends up causing new bone formation and the medullary cavites of the skull can expand outward, which causes enlarged cheeks and a " hair-on-end" appearance on skull x-ray.
与骨组织中的管腔内
续的（包括中央管）。
的
源
，
能向外扩展，在头颅X线上表现为增大的脸颊
及“竖
征”。
