Ankle sprain is an injury of lateral ankle ligaments, happens when it rolls, turns or twists awkwardly. Various other injuries of the outer aspect of the ankle and foot can also mimic ankle sprain. Most of the time ankle sprain is ignored and results in long term morbidity.

Stability of ankle during inward heel movement is less than outward heel movement. While walking on uneven surfaces or during landing if the heel moves more away from the vertical weight bearing axis of the body then its weight forces the heel to move further beyond the capacity of the ligaments and its fibres may get stretched or torn. Other than ligament tendon and bones on the outer aspect of the ankle and foot can also get injured, like peroneal tendon, anterior process of calcaneus, base of 5th metatarsal. Same mechanism of injury can also result in ankle fracture depending on the force affecting the injury.

There are few factors which increases the probability of ankle sprain like,

• Walking and landing on uneven surface
• Participation of sports and recreation activities involved high force landing and pivoting force
• Miscalculation of the distance of landing
• Wearing a faulty or inappropriate footwear, high heel shoe
• Previous ankle injury
• Generalised laxity of the joints
• Inward alignment of heel bone in cavo-varus foot

One may feel a pop at the time of injury followed by pain, swelling, ecchymosis at the lateral aspect of the ankle and inability to walk.