Lateral Ankle Sprains: Do You Actually Need Physiotherapy?

The ankle joint is made up of three bones: tibia (shin bone), fibula (calf bone) and talus. The ankle joint acts like a hinge and allows your foot to move up (dorsiflexion) and down (plantarflexion).

Tibia

• The tibia is the larger of the two leg bones
• It carries most of your body weight and forms the medial malleolus (bony bump on the inside of your ankle)
• Functionally, it acts like the main load-bearing column, transferring weight from your body into your foot

Fibula

• The fibula is the slimmer bone that runs alongside the outside of the leg
• At the ankle, it forms the lateral malleolus (bony bump on the outside of your ankle)
• Although, it doesn’t carry much weight, the fibula is crucial for “lateral ankle stability” and stops the ankle from rolling outwards (known as eversion)

Talus

• The talus sits underneath the tibia and fibula, like a block wedge between them
• The talus is unique because it doesn’t have any muscles attached directly to it; instead it relies on the surrounding ligaments and bones for stability
• the talus also connects to the heel bone (calcaneus) and midfoot, making it the central “bridge” in your foot mechanics

• Prevents the foot from sliding too far forward on the shin
• Most commonly injured when the ankle is rolled inward and downward

PTFL

• Strongest of the three stabilising ligaments
• Limits backward movement of the talus and prevents excessive rotation
• Rarely injured in isolation and is usually torn in severe ankle sprains or dislocations where significant force is applied

CFL

• Provides side-to-side stability, especially when the ankle is in a neutral position or dorsiflexed (toes pointing up)
• Less commonly sprained on its own but is often torn together with the ATFL in moderate to severe sprains (grade 2-3)

Think of these three ligaments like a guy rope on a tent. The ATFL is the thin rope at the front and is useful but vulnerable to snapping. THE PTFL is the thick rope at the back which rarely fails but if it does, the whole structure is compromised. The CFL is the side rope and is strong especially in an upright position.