Which joint classification describes the ankle mortise?

Which joint classification describes the ankle mortise?

• A. Plane
• B. Fibrous
• C. Synovial
• D. Cartilaginous

Answer: (C)

The ankle mortise is a synovial joint, specifically the hinge-type talocrural joint. The socket is formed by the distal ends of the tibia and fibula, into which the talus fits. This arrangement creates a true joint cavity with a synovial lining and articular cartilage on the contacting surfaces, allowing primarily dorsiflexion and plantarflexion on a single axis. That synovial capsule and structured articular surfaces distinguish it from other types. Plane joints involve flat surfaces with gliding movements, which isn’t the main action here. Fibrous joints lack a joint cavity and rely on fibrous tissue, not a synovial capsule. Cartilaginous joints are joined by cartilage with no synovial capsule. Therefore, the ankle mortise is best described as synovial.

The ankle mortise is a synovial joint, specifically the hinge-type talocrural joint. The socket is formed by the distal ends of the tibia and fibula, into which the talus fits. This arrangement creates a true joint cavity with a synovial lining and articular cartilage on the contacting surfaces, allowing primarily dorsiflexion and plantarflexion on a single axis. That synovial capsule and structured articular surfaces distinguish it from other types.

Plane joints involve flat surfaces with gliding movements, which isn’t the main action here. Fibrous joints lack a joint cavity and rely on fibrous tissue, not a synovial capsule. Cartilaginous joints are joined by cartilage with no synovial capsule. Therefore, the ankle mortise is best described as synovial.