Orthopaedic Surgeon

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Tibia

The tibia is the shin bone. At the shops this may be called a shank bone and it is the larger and stronger of the two bones in the leg below the knee. It connects the knee with the ankle bones and is expanded where it enters into the knee-joint, narrows down in the lower third and enlarges (but less) towards the ankle joint.

The tibia is connected to the fibula (the smaller bone in the lower leg) by a membrane which runs between the two bones. There are joints at the top and bottom, called the proximal and distal tibio-fibular joints.

The top of the tibia is quite large and expands into two flattish areas, the medial condyle and lateral condyle.

The top joint lining surface has two smooth facets. The inside facet is oval in shape and is slightly concave from side to side and from front to back. The lateral facet which is nearly circular, is concave from side to side, but slightly convex from front to back. The centre portions of these facets are designed to run against the cartilage lined ends of the femur (thigh bone) while their edges support the menisci of the knee joint (which act as shock absorbers between the two bones).

In the centre of the top of the tibia lie the 'spines' of the tibia. In front of and behind this are rough depressions for the attachment of the anterior and posterior cruciate ligaments and the menisci.

The front surfaces of the top of the tibia are continuous with one another, forming a large somewhat flattened area. This extends down to the tibial tuberosity which is where the patella tendon (patella ligament) attaches.

The back of the condyles are separated from each other by a shallow depression which is where the PCL attaches.

Various muscles attach to or pass by several other areas of the proximal (top end of) tibia.