EVERYDAY SCIENCE

Detailed explanation-1: -The diaphysis is the tubular shaft that runs between the proximal and distal ends of the bone. The hollow region in the diaphysis is called the medullary cavity, which is filled with yellow marrow (containing fat storage cells).

Detailed explanation-2: -The diaphysis, or central shaft, contains bone marrow in a marrow cavity. The rounded ends, the epiphyses, are covered with articular cartilage and are filled with red bone marrow, which produces blood cells (Figure 19.17).

Detailed explanation-3: -The outer walls of the diaphysis (cortex, cortical bone) are composed of dense and hard compact bone, a form of osseous tissue.

Detailed explanation-4: -Most of the diaphysis is formed by compact cortical bone, whereas the inside of the metaphysis and the epiphysis, as well as of short tubular and flat bones contains trabecular (cancellous) bone tissue.

Detailed explanation-5: -Bone marrow fat (BMF) is located in the bone marrow cavity and accounts for 70% of adult bone marrow volume. It also accounts for approximately 10% of total fat in healthy adults above the age of 25 years (1, 2).