tibiae

The tibiae, plural of tibia, are the paired shin bones of the lower leg. They are the larger, medial bones that bear most of the body’s weight and form the main articulation with the femur at the knee and with the talus at the ankle. They are complemented by the slender fibula laterally.

Proximally, each tibia has medial and lateral condyles that articulate with the femoral condyles to form the knee joint. The intercondylar eminence lies between the condyles. The anterior surface carries the tibial tuberosity, where the patellar ligament attaches. The shaft shows an anterior crest and a triangular cross-section; the posterior surface features the soleal line. A nutrient foramen opens on the medial aspect of the shaft, allowing entry of the nutrient artery.

Distally, the tibia widens to form the medial malleolus, which projects medially and contributes to the stability of the ankle by articulating with the talus. The distal tibia also participates in the distal tibiofibular syndesmosis with the fibula, and together they help stabilize the ankle joint.

The vascular supply to the tibia comes mainly from the posterior and anterior tibial arteries, with nutrient arteries entering the shaft. Surrounding soft tissues are innervated by branches of the sciatic nerve, including the tibial and common peroneal nerves.

Clinical relevance is dominated by fractures. Tibial fractures are common due to direct trauma or torsion, with midshaft injuries and distal tibial (ankle or plafond) injuries posing particular challenges. Treatment ranges from intramedullary nailing for shaft fractures to open reduction and internal fixation for articular or complex fractures, often supplemented by immobilization during healing.