tibiatibiofibular

Tibiatibiofibular is a term used to describe the anatomical relationship and functional joint complex between the tibia and fibula in the lower leg. In many anatomical references it encompasses two main regions: the proximal tibiofibular joint near the knee and the distal tibiofibular syndesmosis near the ankle, connected along much of their length by the interosseous membrane.

Proximal tibiofibular joint: This is a plane synovial joint formed between the head of the fibula and the lateral aspect of the tibia's proximal condyle. It allows small gliding movements that accompany knee flexion and extension. Stability is provided by the proximal tibiofibular ligaments (anterior and posterior) and by the interosseous membrane continuing distally toward the shaft of the bones.

Distal tibiofibular syndesmosis: This is a fibrous joint between the distal ends of the tibia and fibula. It is reinforced by the anterior tibiofibular ligament, the posterior tibiofibular ligament, and the interosseous (inferior) ligament, with an inferior transverse component sometimes described. Together, these structures maintain the integrity of the ankle mortise and secure the articulation with the talus.

Function: The tibiatibiofibular complex helps transmit axial load from the tibia to the fibula and across the ankle, while allowing slight, coordinated movement during gait. It stabilizes the ankle mortise, particularly during dorsiflexion and external rotation.

Clinical relevance: Injuries to this complex, especially the distal ligaments, can cause high ankle sprains or syndesmotic diastasis. Lesions such as a Maisonneuve fracture illustrate proximal fibular involvement with distal tibiofibular disruption. Diagnosis relies on clinical assessment and imaging, including X-ray views (often mortise view) and MRI or CT when needed. See also tibiofibular joint, ankle mortise, and syndesmosis.