Tarsal coalition
Tarsal coalition is an abnormal connecting bridge of between two normally-separate tarsal (foot) bones, and is considered a sort of birth defect. The term 'coalition' means a coming together of two or more entities to merge into one mass. The tissue connecting the bones, often referred to as a "bar", may be composed of fibrous or osseous tissue. The two most common types of tarsal coalitions are calcaneo-navicular and talo-calcaneal, comprising 90% of all tarsal coalitions. There are other bone coalition combinations possible, but they are very rare and lack published literature. Symptoms tend to occur in the same location, regardless of the location of coalition: on the foot, just and below the lateral malleolus. This area is called the sinus tarsi.
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