Overview
The tibia is the weight-bearing bone of the leg (crus), between the femur and the tarsus. In cattle the fibula is much reduced: there is no fibular shaft, its proximal end fuses with the lateral condyle of the tibia and its distal end persists as a separate bone, the malleolar bone (os malleolare). The medial surface of the tibia is subcutaneous along its whole length.
Proximal end
- Medial and lateral condyles (condylus medialis and lateralis): articular surfaces for the femoral condyles, via the menisci.
- Intercondylar eminence (eminentia intercondylaris): between the condyles, attachment of the cruciate ligaments and the menisci.
- Tibial tuberosity (tuberositas tibiae): large and cranial; it receives the three patellar ligaments. It continues distally as the cranial border (margo cranialis).
- Fibular remnant: the head of the fibula forms a small prominence fused with the lateral condyle.
Shaft and distal end
- Shaft: triangular proximally and more rounded distally; muscles cover its cranial, lateral and caudal surfaces but not the medial one.
- Cochlea of the tibia (cochlea tibiae): the distal articular surface, with two grooves separated by an intermediate ridge, into which the proximal trochlea of the talus fits.
- Medial malleolus (malleolus medialis): the medial prominence of the hock, palpable.
- Malleolar bone (os malleolare): takes the place of the lateral malleolus; articulates with the tibia, the talus and the calcaneus.
Clinical relevance
- Tibial fractures: occur in calves and adults; because the medial surface is subcutaneous, many are open. Being high on the limb, a standard cast is not enough: a Thomas splint combined with a cast, external fixators or internal fixation are used.
- Physeal fractures of the proximal and distal tibia in calves.
- Haematogenous osteomyelitis in septicaemic calves: the distal metaphysis of the tibia is one of its sites.