physeal

Physeal is an adjective used in anatomy and pediatric orthopedics to denote relation to the physis, the growth plate at the ends of long bones in children and adolescents. The physis lies between the epiphysis (proximal end) and the metaphysis and is responsible for longitudinal bone growth through endochondral ossification.

Structure and function: The growth plate consists of several zones, including reserve (resting), proliferative, hypertrophic, and the zone of calcification/ossification, arranged in columnar groups. Chondrocytes proliferate and are replaced by bone as they advance toward the metaphysis. Growth is regulated by systemic hormones such as growth hormone, thyroid hormone, and sex steroids, as well as local factors, and gradually diminishes with age until physeal closure occurs after puberty.

Clinical relevance: Physeal injuries are common in children and can disturb growth. They are classified by the Salter-Harris system (types I–VI in some schemes), with varying risks of growth disturbance depending on the pattern and treatment. Other conditions affecting the physis include nutritional deficiencies like rickets, endocrine disorders, and physeal arrest after injury. Proper assessment and management are essential to minimize complications such as angular deformities or limb length discrepancy.

Imaging: Radiographs show the physis as a radiolucent line between metaphysis and epiphysis; it remains open in children and closes in adolescence. MRI is useful for evaluating the physis in ambiguous cases and for assessing physeal injuries, especially when radiographs are inconclusive or when soft-tissue involvement is suspected.

Etymology and usage: The term is commonly used in descriptions of bone development, pediatric fractures, and growth disorders, with related terms including physeal plate and growth plate.