The epiphyseal plate is an area at the long end of the bone which contains growing bone. As people develop, the bone grows longer as a result of activity inside the epiphyseal plate, allowing them to grow taller. These growth plates permit growth after birth, allowing the long bones of the body to extend as someone reaches maturity. Once growth is completed and someone reaches full maturity and stature, the new bone slowly ossifies and the epiphyseal 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 which 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 rapidly in children explains why children 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 cancers cells to spread quickly.

Epiphyseal plates can clearly be seen on x-rays. Inspection of these areas is sometimes used to provide more information about unknown 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. This 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 epiphyseal plate, and a resulting reduced stature for the patient.

People with disorders of the bone, including disorders which involve the epiphyseal plate, 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 people develop tools they can use to live with chronic medical issues.