The fibrous tissue that surrounds muscle and separates several tissues of your body is known as the fascia. The underside, or plantar, area in the foot includes a strip of this tough tissue, called the plantar fascia, stretching with the heel to the entrance of the bottom of your foot. https://www.theorthopaedicandpainpractice.com/treating-foot-arch-pain-with-modern-orthopaedic-pain-management-techniques/