Plantar fasciitis

Plantar fasciitis, is the most common cause of pain at the underside of the heel, accounting for around 15% of all painful foot conditions. The plantar fascia is a long tough band of connective tissue (ligament) that connects your heel bone to your toes. It acts like a bowstring providing spring in raising the arch of your foot during the push-off phase of walking.

Usually, the onset of pain in the heel is gradual.  The pain is usually worse taking the first steps in the morning when getting out of bed or after sitting for a prolonged period of time, and is often accompanied by limping. The pain is frequently described as "like stepping on a sharp stone" or having a “stone bruise”. Typically, the heel pain eases after walking for some time but intensifies by day's end if weight bearing for a long time or at the end of a long walk.

The incidence of plantar fasciitis peaks between the ages of 40 and 60 years in the general population. It also occurs in younger people who are runners or in occupations that require prolonged standing. It's been reported to account for about 10% of running injuries and is common among military personnel. In a significant number of cases the strain occurs in non-weight bearing activities. It affects both feet in up to 30% of cases.

Reports on microscopic examination of tissue samples of chronic plantar fasciitis show degenerative changes in the connective tissue at the site of attachment of the plantar fascia to the heel bone, suggesting it is a condition that gradually develops over time caused by excessive tension strain on the plantar fascia.

There is no inflammation suggesting the suffix should be -osis (denoting an abnormal formation) not -itis (denoting inflammation), that is plantar fasciosis. Excessive tension strain by the plantar fascia on the heel bone can lead to a heel spur.