Plantar fasciitis is a painful swelling of the thick tissue at the base of the foot, called the plantar fascia. It is one of the most common orthopedic complaints relating to the foot.

The plantar fascia is a thick band of tissue which covers the bones at the bottom of the foot. It originates from the calcaneum bone that makes up the heel, and fans out towards the toes covering the bottom of the foot. Its main function is to provide protection to the foot from bottom side by acting as a shock-absorber and as an arch support.