Ankle Sprain

 

Bony Anatomy

The ankle is comprised of the distal tibiofibular joint, talus and the subtalar joint.  There are three ligaments on the outside of the ankle: front (anterior talofibular ligament); side (talofibular ligament) and back (fibulocalcaneal ligament).  On the inside is a ligament called the deltoid ligament.

Movement at the Ankle

The ankle can move the foot pointing or flexing; The ankle can turn inward and slightly outward.  The ankle can also rotate slightly inward and outward. Three planes of movement.

 

Mechanism of Injury

Excessive turning inward at the ankle due to landing on someone's foot; and /or planting quickly with the ankle and the muscles around the ankle unable to respond quick enough to the excessive forces.

 

The Injury

Most ankle sprains involve the outside ankle ligaments due to an excessive turning inward of the ankle and foot.

Severity of Sprain

Grade I Ankle Sprain

Catogorized with minimal joint laxity and damage to the front outside ligament (anterior talofibular ligament).

Grade II Ankle Sprain

Moderate joint laxity and damage to the front and side ligaments on the outside of the ankle.  Moderate swelling and discoloration.  X-ray needed to rule out avulsion fracture to the outside bone(the fibula) where the ligaments attach.

Grade III Ankle Sprain

Severe joint laxity with damage to all three outside ligaments with moderate to severe swelling and discoloration.  X-ray needed to rule out avulsion fracture that may need to be repeated due to a bad picture from excessive swelling.