It extends between the medial process of the tuber calcanei[1] and the proximal phalanges of[citation needed] the toes.

[1] Distally, the plantar fascia becomes continuous with the fibrous sheaths enveloping the flexor tendons passing to the toes.

In an experiment using cadavers, it was found that failure of the plantar fascia averaged at loads of 1189 ± 244 newtons[3] (121 ± 24 kgf or 267 ± 55 lbf).

Failure most often occurred at the proximal attachment to the calcaneus, which is consistent with the usual location of symptoms (i.e. in plantar fasciitis).

Although most of the figures mentioned above are from either cadaver studies or investigations using models, they highlight the relatively large load the plantar fascia is subjected to while contributing to the structural integrity of the foot.

When the toes are dorsiflexed in the propulsive phase of gait, the plantar fascia becomes tense, resulting in elevation of the longitudinal arch and shortening of the foot (see 3A).