Lower limb

Tibia

Before you say anything

The tibia is the weight-bearing bone of the leg and the easiest of the pair to identify: it is far larger, and the shin you can feel on yourself is its subcutaneous medial surface. Side determination hangs on one projection — the medial malleolus — and the examiner will usually follow with why compound fractures are so common here.

Which side? Three checks

Hold it like this first: Hold it vertically with the expanded condyles uppermost, the medial malleolus projecting downwards from the lower end on the medial side, and the sharp anterior border facing forwards.

Check 1 — Compare the ends
One end is much broader, with two flat condyles
That is the upper end
Check 2 — Find the malleolus
A stout process descending from one side of the lower end
That is the medial malleolus, so it points to the midline and away from the side the bone belongs to
Check 3 — Find the notch on the lower end
A rough hollow on the opposite side of the lower end
That is the fibular notch and it is lateral, confirming the side

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Say these first

The larger of the two leg bones
Two flat condyles with an intercondylar area above
A medial malleolus and a broad subcutaneous medial surface

Do not confuse it with

The fibula
The tibia is stout and weight-bearing with two condyles above; the fibula is slender with a small head above and a flattened lateral malleolus below that descends further than the medial malleolus.

Examiner trap

Assuming the growing end is the lower end because it is in the radius and ulna. In the lower limb the growing ends are at the knee — lower femur, upper tibia and upper fibula.

Memory hook

Grow away from the elbow, grow towards the knee.

Why it matters

Because the medial surface is subcutaneous, tibial fractures are frequently compound and the poor soft-tissue cover makes union slow.
The proximal anteromedial tibia is the standard site for intraosseous access in a child when a vein cannot be found.
Traction apophysitis at the tibial tuberosity in an active adolescent is Osgood-Schlatter disease.
The tibia transmits nearly all the weight from the femur to the talus; the fibula transmits very little.

Senior’s 30-second takeaway

Tibia — the whole bench in four lines. Read this on the way in.

If you see this: The larger of two leg bones · Two flat condyles above · A malleolus descending on one side below
If asked to identify it: This is a tibia; the medial malleolus at the lower end lies medially and the fibular notch laterally, which gives the side.
If asked one more: The upper end is the growing end and its centre is present at birth in a full-term infant.
If asked why it matters: Its subcutaneous medial surface is why tibial fractures are so often compound.

Then stop. Let the examiner ask the next question.

🩺 Before you say anything

Which side? Three checks

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Senior’s 30-second takeaway

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Before you say anything