Tibia: The tibia contains two condyles, the medial and lateral which are separated by the intercondylar eminence. Both condyles include the articular areas on their proximal surfaces and the adjacent nonarticular parts of the proximal extremity. The semimembranosus is inserted on the medial condyle. Two biconcave fibrocartilages, the menisci, fill part of the space between the apposed condyles of the femur and tibia, making the joint consistent with one another. The intercondylar eminence consists of two small, elongated tubercles, which form its highest part, and a shallow intercondylar area. The cranial intercondylar area is a depression cranial to the eminence and in large part between the condyles.
Found on the proximocranial surface of the tibia is the tibial tuberosity to which the quadriceps femoris, the biceps femoris, and the sartorius attach. Found on the distal extremity of the tibia is the tibial cochlea, the articular surface, which consist of two grooves that receive the ridges of the proximal trochlea of the talus.
Clinical Correlation: Fractures of the tibia are relatively common in dogs and cats, comprising 21 percent of long-bone fractures, and 11.7 percent of appendicular fractures.