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Ankle Joint Eversion and Inversion

Posted by KinX Learning on October 06, 2016 . 0 Comments

The two movements of the foot in the subtalar joint are not true ankle joint movements but are usually referred to as ankle movements. They are inversion and eversion, which take place between the talus (ankle bone), the navicular (tarsal bone), and the calcaneus (heel bone).

 

In inversion, also known as adduction or supination, the sole of the foot is turned inward and upward. In eversion the foot is turned outward and downward, that is, the toe area of the foot is pointed outward. These movements are an important part of the pushing-off actions required by athletes in many sports. Development of the muscles involved in eversion and inversion helps prevent ankle sprains. In running, pronation and supination respectively are the terms most commonly used for these actions. Note that the precise meaning of these terms is different, depending on whether it is in medicine, podiatry, sports, chiropractic, physical therapy, etc. The exact definitions vary depending upon the field. However in sports, the most common terms are inversion and eversion and thus they will be used in this text.

 

Having muscle strength on both sides of the ankle and foot is important in maintaining joint integrity. Any imbalances in the strength or flexibility of the surrounding musculature result in misalignment. This in turn must be counteracted by muscular contractions or ligament tension. If not, postural imbalances occur.

 

Athletes with shin splints usually have significantly greater plantar flexor (extensor) strength than dorsiflexor (flexion) strength and greater movement of the calcaneus during the support phases of running and walking. Over development of the ankle extensors tends to also cause a muscular imbalance between the strength of the foot supinator and pronator muscles, which may result in lateral ankle sprains, particularly when landing after being airborne.