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What is an Inversion Ankle Sprain?

inversion sprain

by Corey Vanderwouw, MPT, published in The Union

The inversion sprain is the most common type of ankle sprain, comprising approximately 25% of all sports injuries. It is commonly referred to as rolling the ankle, and also known as a low ankle sprain. Many, if not most of us, have experienced this type of injury either in sports or from tripping. During the inversion sprain, a person’s ankle will roll inward and weight is placed on the foot and ankle in this vulnerable position. It is a common injury in sports that include high velocity and high-impact movements such as basketball, soccer and football.

An ankle inversion sprain is a tearing and overstretching of the lateral (outer side) ligaments by excessive force or trauma. Ligaments are the connective tissue that join one bone to another and stop excessive movement from one bone away from another. The three primary lateral ankle ligaments consist of the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and posterior talofibular ligament (PTFL). The ATFL is the most commonly injured of these ligaments. When a person experiences an inversion sprain they will likely experience ankle pain, edema (swelling), decreased range-of motion, and loss of function including difficulty walking.

 There are three categories of inversion sprains: Grades I, II, and III. Grade I is a mild sprain with minimal ligament tearing and resulting minor excess ligament laxity. Typically, a small amount of pain and edema are present. Grade II is a moderate sprain where more ligament tearing and laxity occur. The pain and swelling are more prolonged than those of a Grade I sprain. The ankle may feel loose, or the excess mobility may not be felt right away due to the stiffening effects of edema. Bruising may also be present, and it may be difficult to put weight on the ankle.

Grade III is a complete rupture of one or more of the ankle ligaments. The level of pain is typically fairly severe, with severe pain and edema. It is also typically very painful to bear weight on the ankle.

Following an inversion sprain, ankle ligaments can be elongated or completely ruptured due to the tearing that has occurred. This causes joint movement that is in excess of what is the ankle’s normal movement is. This is referred to as mechanical instability.


Besides mechanical instability, a sprained ankle can be affected by Functional Ankle Instability (FAI).


This is instability that is created by sensory and motor changes that occur in the ankle due to a sprain. Sensory receptor activity of cutaneous nerves (sural nerve and distal superficial peroneal nerve) and joint receptor activity diminish, providing the brain with less information regarding ankle position during movements. In response, our bodies are less able to react to the forces that are happening at the ankle.


An inversion sprain can also affect ankle muscles, as well as the gluteus maximus (buttocks), biceps femoris (back of thighs), and even the erector spinae (back muscles). These changes make the ankle susceptible to further injury.


Acute ankle sprains are commonly treated immediately with anti-inflammatory modalities which include ice with elevation and natural analgesics to reduce edema and pain. There is a standard protocol referred to as “MEAT” to treat ligament and tendon injuries which stands for Movement, Exercise, Analgesics and Treatment. It is advisable to seek a doctor or physical therapist for an acute ankle sprain to get individualized recommendations that are dependent on the severity of the sprain. Depending on the extent of the sprain, rehabilitation may be appropriate to improve weight bearing, help restore normal walking, and improve joint and sensory receptor activity with neuromuscular retraining and muscle reconditioning. Your doctor or physical therapist may also recommend the use of an inversion sprain ankle brace, orthotics or sports taping. In addition, if you feel that you have loose, unstable or painful ankles, ask your doctor or physical therapist for help.

Whether you’re out playing sports this winter or taking a stroll, make sure you’re wearing stable, well-fitting shoes, and watch out for slippery and uneven surfaces. During this time of year when the leaves fall, and the coming rain will create more challenging walking surfaces, it is best to stay aware and protect your ankles.

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