Ankle Inversion Injuries

Anatomy of the Ankle

The ankle is a joint complex consisted of 2 articulations:

1)   Talo-Crural



(Side View of Right Foot)

Sometimes referred to as the true ankle joint, this dome-shaped bone is connected to the 2 bones of lower leg (Tibia & Fibula). Because of its’ shape, it is responsible for pointing your ankle up (dorsiflexion) and for pointing your ankle down (plantarflexion).


2)  Subtalar


(Side View of Right Foot)

This is the joint under the dome (Talus) of the ankle joint. Anatomically, the talus rests on the heel bone called the Calcaneous.

Because of its’ shape, the subtalar joint allows the foot to turn inwards (inversion) and outwards (eversion).


Mechanism of Injury

Most ankle sprains occur when the ankle is twisted inwards (inversion).

Because sprains happen very quickly, structures on the outside (lateral) aspect of ankle are commonly injured.


Which Structures Can Potentially Be Injured?

  • Ligaments  
  • Tendons
  • The Fibula Bone

Injuries to these structures do not have to be mutually exclusive and can take place concurrently.

1) Ligaments


(Side View of Right Ankle)

There are 3 ligaments that stabilize the outside (lateral) aspect of the ankle joint complex. They are:

  1. Anterior Talo-Fibular (ATF) Ligament,
  2. Calcaneo-Fibular (CF) Ligament , &
  3. Posterior Talo-Fibular (PTF) Ligament

With inversion sprain, any or all of these 3 ligaments can be injured together but because of how these ligaments are sequenced (i.e. ATF ligament in front followed by CF ligament, then PTF ligament), it is common for the ATF ligament to be injured first followed by CF ligament, and lastly the PTF ligament.

What are The Signs & Symptoms associated with Ligament Sprain?

  • Pain & Swelling
  • Loss of Range of Motion
  • Weakness
  • Tenderness to Touch
  • Difficulty with Walking & Weightbearing


Is X-Ray Useful?
For serious sprains, x-ray is indicated to help and rule out whether there is fracture of the fibula bone. X-rays cannot show ligament sprains.

What are the Treatment Options?

Unless the sprain is of serious in nature involving complete tears, most ligament sprains are managed conservatively.



2) Tendons


(Side View of Right Lower Leg & Ankle)

Muscles on the outside (lateral) aspect of the lower leg is called the Fibularis (formerly known as the Peroneus) group. It is consisted of two muscles/tendon:

  • the Longus (which means the longer) and
  • the Brevis (which means the shorter).

During an inversion sprain, some people may try to save the inverting action by spontaneously contracting the fibularis muscle group but unfortunately, without much success, thereby resulting in injury of this muscle group.

What are The Signs & Symptoms associated with Tendinitis?

  • Pain & Swelling
  • Loss of Range of Motion
  • Weakness
  • Tenderness to Touch
  • Difficulty with Walking & Weightbearing

Is X-Ray Useful?

For serious sprains, x-ray is indicated to help and rule out whether there is fracture of the fibula bone. X-rays cannot show tendinitis. Inflammation and swelling of the Fibularis tendons can sometimes be revealed by Diagnostic Ultrasound.

What are the Treatment Options?

Tendinitis is usually treated conservatively as by:


3)  Fracture of Fibula


(Side View of Right Ankle)

The 3 ligaments (ATF, CF, PTF) as previously discussed are connected to a specific part of the fibula bone called the Lateral Malleolus. This is the rounded bone of your ankle.

During a forceful and quick inversion sprain, stress associated with the action of inverting may transmit through the ligaments into the lateral malleolus causing it to break.


Where a fracture is suspected, x-ray must be done to confirm or rule out such fracture.

Where fracture is confirmed, an orthopaedic surgeon should be consulted for management options including casting or surgery.



(Rear View of Right Ankle)

Physiotherapy, for purpose of rehabilitation after casting and/or surgery, may be indicated to promote ankle range of motion, strength, & balance (proprioception) as well as function (i.e. walking).