Acute Ankle Sprains
The word acute usually means within the past six (6) weeks. This is the most common injury of the foot and ankle and almost 25,000 people sprain their ankle each day. The most common way people sprain their ankle is by turning the ankle inward, which is called supination or inversion by your doctor. When your ankle turns in, you put strain on the outside (lateral) aspect of your ankle which most commonly sprains the ligaments holding your outside bone (fibula) to your ankle bone (talus) or to your heel bone (calcaneus).
The ligament most commonly torn by an ankle sprain is called the anterior talo-fibular ligament, or ATFL for short. Sometimes with severe sprains, the ligament on the inside of your ankle, called the deltoid ligament can be torn. "High ankle sprains" are the most severe types of sprains involving the ligament that connects the tibia and fibula together ; the syndesmosis.
Your doctor will typically grade the sprain based on severity of the ligament injury. Grade 1 is a simple stretch of the ligament. Grade 2 involves a partial tear. Grade 3 involves a complete tear.
Luckily, most sprains heal easily with simple treatment.