What is the Epiphyseal Plate?

The epiphyseal plate is an area at the long end of the bone that contains growing bone. As people develop, the bone grows longer as a result of activity inside this area. These plates permit growth after birth, allowing the long bones of the body to extend and a person to grow as he or she reaches maturity. Once growth is completed and the person reaches full maturity and stature, the new bone slowly hardens and the plate turns into the epiphyseal line.

This area, also known as the metaphysis, is located between the epiphysis, at the end of the bone, and the diaphysis, the shaft of the bone. The epiphyseal plate is comprised of cartilage that reproduces rapidly to lengthen the bone, with the rate of new bone production outstripping the rate of bone destruction. This tendency for bone to grow quickly in children explains why they often heal more quickly from fractures than adults do. It can also, unfortunately, put children at risk for cancers of the bone, because the rapid replication can allow cancer cells to spread quickly.

The growth plates can clearly be seen on X-rays. Inspection of these areas is sometimes used to provide more information about bones. The plates fuse over at a stable and predictable rate, so someone with experience can examine a bone and make an estimate of its age. After about age 25, when the epiphyseal lines are fully formed, examination of this area of the bone can be less useful, as it may do little more than confirm that the bone belonged to a fully grown adult.

It is possible to experience a fracture of the epiphyseal plate. This area of the bone may also fail to produce new bone as expected, which can lead to dwarfism, as the patient's long bones fail to elongate during periods of growth. A form of dwarfism known as achondroplasia, for example, causes abnormalities with the growth of new bone at the plate, and a resulting reduced stature for the patient.

People with disorders of the bone may see a variety of specialists, depending on the nature of the issue. Bone specialists, geneticists, radiologists, and oncologists all work with people who experience bone disorders, as do people like physical therapists and occupational therapists, who help patients develop tools they can use to live with chronic medical issues.