Calcaneus

The calcaneus (from the Latin calcaneus or calcaneum) is one of the seven bones of the foot or tarsus, short, asymmetrical and irregular. It has taken its name from calcare ('to step on'), because it is the bone that forms the heel. Its anterior-posterior diameter is the largest. It consists of six faces or sides: top and bottom, sides, and front and back. This bone forms the heel of the foot.

It is located in the posterior row, directed from posterior to anterior next to the talus and scaphoid. It articulates with the talus cranially and with the cuboid anteriorly. It constitutes the first point of support of the foot during walking, located in one of the worst irrigated areas of the body and protected by the plantar pad of adipose tissue or plantar fat formed by columns of adipose tissue separated by partitions of fibrous tissue, it covers it plantarly the plantar aponeurosis or fascia, this plantar fat has a cushioning function, which is involved in various diseases, such as fasciitis or heel spurs.

The position of the calcaneus in relation to the talus (subtalar joint) and to the ground determines the position of the hindfoot (rear part of the foot formed by the talus and calcaneus) in varus, valgus, or neutral. The varus hindfoot and, above all, the valgus hindfoot, are responsible for different diseases of the locomotor system and contribute to the appearance of alterations in the normal physiological gait, with important clinical consequences (pain, overloads, flattening, muscle fatigue, bunions, etc.) both at the foot level and at the level of the lower limb. From all this it follows that its spatial positioning is very important to contribute to a correct gait and to the health of the rest of the joints of the foot.

Structure

Calcáneous bone, represented with green color.

Calcáneo in red.

It is a bone that, being cubic, has 6 faces, whose details are:

• Internal face: The medial or internal surface is concave and displays a prominent feature on its upper edge (the astrologer's sustenta) that is projected in the medial sense and supports the back of the head of the astral. The lower face of this astrágalo sustenta has a marked groove that runs from post to previous, along which the long bending muscle tendon of the big toe runs to the sole of the foot.
• External face: Larger on the back than before, it is flattened and has two slopes for the lateral butneo muscles, it has the butneal throcle.
• Previous face: It is convex transversally and concave from top to bottom, it is articulated with the cuboids and forms the major apophysis of the calcáneo.
• Later face: It is convex and tuberculosis and gives the insertion for the Achilles tendon
• Upper face: It has a cross-sectional convex surface and a previous excavation with two joint faces, a later convex and a previous concave and oblong (longer than wide) that is in a portion of bone called apophysis less of the calcáneo, separated by a groove for the insertion of ligaments and articulated with the astrágalo (sarticulation subaga).
• The lower face: The lower side is narrow and rough, has two tuberosities of uneven volume, forming the calcañar or back of the sole of the foot and an earlier tuberosity that together form the trigone of the calcáneo.