What is the growth plate called, and when does it typically close?

• A. Epiphyseal line
• B. Articular cartilage
• C. Medullary cavity
• D. Epiphyseal (growth) plate; it typically closes after adolescence

Answer: (C)

The growth plate is the epiphyseal plate, a cartilage layer between the end part (epiphysis) and the shaft (diaphysis) of long bones. It stays cartilage while you’re growing, allowing lengthwise bone growth as cells divide and are replaced by bone. During puberty, hormones accelerate ossification, and the growth plate gradually closes, leaving a thin line called the epiphyseal line once growth stops. So the growth plate is the epiphyseal plate, and it typically closes after adolescence. The other structures mentioned—articular cartilage at joint surfaces, the medullary cavity in the bone’s center, and the epiphyseal line as the closure remnant—are related but refer to different parts or states of bone.