Metafyse

Metafyse, also called the metaphysis, is the wide portion of a long bone situated between the epiphysis (the end part near a joint) and the diaphysis (the shaft). In growing individuals, the metaphysis lies adjacent to the epiphyseal plate, or growth plate, and forms a transition zone through which the bone lengthens. The region contains predominantly trabecular (spongy) bone surrounded by a thin cortical shell and has a rich network of blood vessels that supports rapid bone formation and remodeling during growth.

Function and structure: The metaphysis serves as the site where new bone is produced as the bone increases in length. It is intimately involved in endochondral ossification at the growth plate, with cartilage being progressively replaced by bone tissue as the limb grows. The vascular supply to the metaphysis facilitates this rapid turnover and repair.

Development and maturation: With skeletal growth, the metaphysis expands as the growth plate pushes the epiphysis away from the diaphysis. When growth ceases and the growth plate fuses, the metaphyseal region becomes part of the mature bone shaft, and the boundary between diaphysis and epiphysis becomes less distinct. The metaphysis remains anatomically distinct from the diaphysis, though its growth-related activity diminishes.

Clinical relevance: Metaphyseal fractures are common in children due to the relative pliability of their bones and may involve the growth plate, potentially affecting future growth. The metaphyseal region is also a common site for hematogenous osteomyelitis in pediatric patients. Radiographs typically show the metaphysis adjacent to the growth plate, with remodeling patterns reflecting ongoing growth in younger individuals.