From what region does the growth in length of a long bone occur?

The growth in length of a long bone occurs primarily at the epiphyseal cartilage, also known as the epiphyseal plate or growth plate. This area is located between the epiphysis and the diaphysis of the bone and consists of hyaline cartilage that is responsible for the elongation of the bone during childhood and adolescence.

As a person grows, new cartilage is formed at the epiphyseal plate, which gradually ossifies to become bone tissue. This process allows for the increase in length of the long bone. Once growth is complete and adulthood is reached, the epiphyseal plate becomes fully ossified, and the bone stops growing in length.

Other areas of the bone, such as the diaphysis, medullary cavity, and articular cartilage, have different functions and do not contribute to the lengthening process. The diaphysis refers to the shaft of the bone; the medullary cavity is the central cavity containing bone marrow; and articular cartilage covers the surfaces of bones at joints, which facilitates movement and reduces friction but does not play a role in lengthening the bone.