Tibia (shin bone)

What it is

The tibia runs from the knee to the ankle and carries most of your body weight. Its upper end (the proximal tibia) has two shallow joint surfaces, medial and lateral, which together make up the tibial plateau. The menisci sit on these surfaces, and the cruciate ligaments attach to a raised area between them.

At the front, just below the kneecap, is a bony bump called the tibial tubercle, where the patellar tendon attaches. You can feel it under the skin.

Why it matters for patients

The tibia is involved in several knee conditions. Falls and road traffic accidents can cause tibial plateau fractures. In growing children, the tibial tubercle is where Osgood–Schlatter disease causes a tender lump. The angle of the upper tibia decides whether a leg is bow-legged or knock-kneed, which affects how load passes through the knee and can speed up wear on one side. That is why a high tibial osteotomy, which reshapes the upper tibia, is an option for some younger patients with one-sided arthritis.

How it is examined

X-rays, including long-leg standing films, show the tibia and leg alignment. A CT scan maps fractures in detail, and an MRI shows bone bruising and the soft tissues attached to the plateau.