What is the metaphysis of a long bone?

• A. The region where the diaphysis and epiphysis meet, containing the growth plate
• B. The central shaft of the bone, primarily composed of compact bone
• C. The outer fibrous layer that covers the entire bone except at joint surfaces
• D. The rounded end of the bone, covered with articular cartilage

Answer: (A)

Verified step by step guidance

1. Understand the structure of a long bone: A long bone typically consists of three main parts - the diaphysis (shaft), the epiphysis (ends), and the metaphysis (region between the diaphysis and epiphysis).
2. Identify the metaphysis: The metaphysis is the region where the diaphysis and epiphysis meet. It is crucial during growth as it contains the growth plate, also known as the epiphyseal plate.
3. Differentiate the metaphysis from other parts: The diaphysis is the central shaft of the bone, primarily composed of compact bone. The epiphysis is the rounded end of the bone, covered with articular cartilage. The periosteum is the outer fibrous layer that covers the entire bone except at joint surfaces.
4. Recognize the function of the metaphysis: During childhood and adolescence, the growth plate in the metaphysis is where new bone is produced, allowing the bone to lengthen.
5. Conclude the identification: Based on the description, the metaphysis is specifically the region where the diaphysis and epiphysis meet, containing the growth plate, which is essential for bone growth.