Which joint is immovable and cartilaginous, exemplified by growth plates in children?

• A. Suture
• B. Interosseous membrane
• C. Epiphyseal plate
• D. Intervertebral disc

Answer: (C)

Growth plates are a prime example of a cartilaginous joint that is effectively immovable. In children, the epiphyseal plate is a layer of hyaline cartilage between the epiphysis and diaphysis of long bones. This arrangement, called a synchondrosis, holds the bone ends together while still allowing lengthwise growth as cartilage is replaced by bone in a controlled way. As maturation occurs, the cartilage is gradually ossified to form the epiphyseal line, and growth ceases.

Sutures, by contrast, are fibrous joints between skull bones and are not cartilaginous. Interosseous membranes are also fibrous connections between bones. Intervertebral discs are fibrocartilaginous joints that permit some movement, not completely immobile.