GLOSSARY

Cartilaginous joints are joints in which bones are united by cartilage and have no joint cavity; they are usually immovable or slightly movable.

Types

• Synchondrosis: union by hyaline cartilage; usually temporary and immovable, as in the growth plate, which ossifies after puberty, and the joint between the first rib and sternum.
• Symphysis: union by strong, flexible fibrocartilage; slightly movable and permanent, as in the intervertebral discs and pubic symphysis.

Function

Symphyses provide a combination of strength and flexibility: each intervertebral disc allows little movement, but the sum of 23 discs gives the spine considerable mobility. Fibrocartilage also absorbs and distributes pressure.

Relevance to Sport

• Intervertebral disc: the most important cartilaginous joint in sport; disc herniation and degeneration are common causes of back pain.
• Pubic symphysis: the site of pubic-related groin pain in footballers.
• Growth plates: as synchondroses, they are vulnerable in adolescent athletes.