Plantar fasciitis is a condition resulting in pain and inflammation of the plantar fascia. The plantar fascia, also called the plantar aponeurosis, is a thick band of connective tissue originating on the calcaneus and inserting into the ball of the foot. The plantar fascia is composed of three distinct structural components: the medial, central, and lateral bands. The medial band is a small slip of fascia that originates off the central band and overlies the abductor halluces muscle. The central band comprises the majority of the plantar fascia and overlies
the flexor digitorum brevis muscle. The lateral band is a separate and distinct band that originates off the lateral process of the calcaneal tuberosity and overlies the abductor digiti minimi muscle.

Although pain may occur along the entire course of the plantar fascia, it is usually limited to the inferior medial aspect of the calcaneus, at the medial process of the calcaneal tubercle. Plantar fasciitis often presents as “first-step pain,” which is pain when the patient first gets out of bed in the morning or gets up after periods of rest.

A heel spur may or may not be present but is rarely the source of the pain. The spur is actually located at the origin of the flexor digitorum brevis muscle, which is deep to the plantar fascia.

Causes include poor foot mechanics due to pes planus or pes cavus, obesity, inappropriate footwear,
tight triceps surae, fat pad atrophy, and repetitive microtrauma.