Anatomy · Joints & cartilage

Plantar fascia

Also the plantar aponeurosis

Lower limb · sole of the foot

The plantar fascia (plantar aponeurosis) is a thick, tough sheet of connective tissue on the sole of the foot. It runs from the heel bone to the bases of the toes, splitting into five slips, and it supports the longitudinal arch. When the toes are extended the sheet tightens and lifts the arch, the windlass mechanism. Inflammation or degeneration at its heel attachment, plantar fasciitis, is a leading cause of heel pain.

How to spot them

▸A thick fibrous band on the sole, from the medial tubercle of the calcaneus to the toes in five slips
▸Lies just under the skin and fat, over the short muscles of the sole
▸Fibres merge with the flexor sheaths and plantar plates of the toes
▸Tightens when the big toe is pulled up (dorsiflexed): the windlass mechanism

What to know

A broad fibrous sheet on the sole, from the heel bone to the toes, like the string of a bow beneath the arch

Plantar fascia — the plantar aponeurosis.

Pulling the big toe up tightens it like a windlass and raises the arch of the foot

Plantar fascia — the windlass mechanism (Hicks, 1954).

Sharp heel pain with the first steps of the morning, common in runners and people on their feet all day

Plantar fascia — plantar fasciitis.

A bony spike at the heel is often seen on X-ray in this condition, but is not in itself the cause of the pain

Plantar fascia — the calcaneal spur.

Narrow at its heel attachment, it fans out into five slips towards the toes

Plantar fascia — five digital slips.

Key ideas

Bowstring and windlass: the fascia acts as a tie beam holding the arch, and tightens when the toes extend.

Quick-fire facts

•Attaches proximally to the medial tubercle of the calcaneus and divides into five digital slips distally.
•Plantar fasciitis typically causes pain at the heel, worst after rest, such as the first steps in the morning.
•Risk factors include obesity, running, tight calves and prolonged standing (NHS).
•The windlass mechanism was described by J. H. Hicks in 1954.
•The calcaneal spur is frequently seen with plantar fasciitis but does not cause the pain.
•It is the deep fascia of the sole; the plantar aponeurosis is the thickened central part.
•Treatment: rest, stretching, supportive footwear, injections or surgical release in resistant cases.

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Sources

NHS — Plantar fasciitis