Talon-calcaneal joint

The talocalcaneal joint (lat. articulatio talocalcanea) is the articulation between the talus and calcaneus, forming the base of the hindfoot.

The talus consists of a body, neck, head and posterior process. The calcaneus has a body and two surfaces: the anterior one, formed by the cuboid bone, and the posterior one, called the talus surface.

The talocalcaneal joint is formed between the talus process of the talus and the inner surface of the calcaneus. This joint is spherical, strengthened by a powerful ligamentous apparatus, allowing movements in it within 45 degrees.

In front, the joint is strengthened by ligaments: the anterior talofibular, calcaneofibular and calcaneonavicular, and in the back by the talonavicular-calcaneal and talocuboid.

**Talocalcaneal joint**

The talocaleonavicular joint is formed by the acetabulum (fossa) and the supratalar surface of the calcaneus. It is reinforced in front and sides by reinforcing ligaments, and in the back by the articular labrum and a wide ligamentous bursa. The anterior part of the supratalus eminence serves as an articular tubercle, the anterolateral and posterolateral surfaces of which correspond to the facets of the trochlea of ​​the talus, and the posteroinferior part corresponds to the surface of the talus notch.

Movement in the joint is of an extensor-rotational nature and occurs around the frontal axis. The degree of mobility is limited by the ligaments of the joint. The axis of rotation passes through the axis of rotation of the ankle joint and is directed medially. The direction of the axis of rotation corresponds to the direction of the facet plane of the joint bones (antero-posterior or transverse plane).

The joint is especially important for walking, as it supports the weight of the human body when standing and moving. The joint brings the foot into a state of necessary balance. A normal range of motion in the joint indicates the preservation of its functional properties, which is very important for the normal functioning of the arch of the foot. However, both lateral and rotational mobility of the talus joint is always limited due to the narrowness of the articular surfaces. Thus, extension and rotation (“dancing”) of the foot can occur until the moment when the edges of the articular facets are so close to each other that the joint space almost completely disappears. Lateral deviation of the joint is further limited by the medial and lateral reinforcing surfaces of the talus and calcaneus, which inhibit both extensor and lateral mobility of the joint. Under these conditions, the limitation of the functionality and mobility of the joint is even more dependent on the dysfunction of the block caused by changes in the anatomy and topography of the articular surface of the talus. These changes are the basis for the development of the main foot deformity - flat feet, which makes walking much more difficult.