Veterinary Gross Anatomy

BONE MARROW

There are two kinds of marrow - red and yellow.

Red marrow

• It occupies the interstices of spongy bone everywhere and medullary cavity of long bones at birth. After birth, the red marrow is gradually replaced by yellow marrow.
• Red marrow is an important blood forming substance and contains precursors of erythrocytes, granular leukocytes of the blood, giant cells, which give rise to platelets and a few fat cells.
• In the adult, red marrow is present only in the vertebrae, sternum, ribs, skull bones and epiphyses of long bones.

Yellow marrow

• It consists of ordinary adipose tissue especially in the medullary cavity of long bones and short bones.
• Yellow marrow fills the spaces of the spongy bone in short bones (carpals and tarsals) and medullary cavity of long bones.