Aponeurosis plantaris

The plantar fascia is the thick connective tissue (aponeurosis) which supports the arch on the bottom (plantar side) of the foot.

It runs from the tuberosity of the calcaneus (heel bone) forward to the heads of the metatarsal bones (the bone between each toe and the bones of the mid-foot).

The plantar fascia is a broad structure that spans between the medial calcaneal tubercle and the proximal phalanges of the toes.

Recent studies suggest that the plantar fascia is actually an aponeurosis rather than true fascia.

The Dorland’s Medical Dictionary defines an aponeurosis as: (i) a white, flattened or ribbon-like tendinous expansion, serving mainly to connect a muscle with the parts that it moves, (ii) a term formerly applied to certain fasciae.

Further, it defines the plantar aponeurosis as bands of fibrous connective tissue radiating toward the bases of the toes from the medial process of the tuber calcanei (posterior half of the calcaneus).

The plantar fascia is made up of predominantly longitudinally oriented collagen fibers.

There are three distinct structural components: the medial component, the central component (plantar aponeurosis), and the lateral component (see diagram at right).

The central component is the largest and most prominent.

In younger people the plantar fascia is also intimately related to the Achilles tendon, with a continuous fascial connection between the two from the distal aspect of the Achilles to the origin of the plantar fascia at the calcaneal tubercle.

However, the continuity of this connection decreases with age to a point that in the elderly there are few, if any, connecting fibers.