The plantar fascia has three cords: the central cord (the large clinically familiar band) and the smaller medial and lateral cords. The lateral cord arises from the lateral calcaneal tuberosity and inserts on the base of the fifth metatarsal and the plantar skin of the little toe ray. It forms the inferior boundary of the abductor digiti minimi compartment and contributes to the lateral longitudinal arch support.
Maintains the lateral longitudinal arch integrity; provides the inferior boundary of the abductor digiti minimi compartment on the lateral plantar surface; distributes load along the lateral column of the foot during gait.
The lateral cord of the plantar fascia is less commonly symptomatic than the central cord but can develop independent lateral plantar fasciitis producing lateral heel and forefoot pain distinct from the medial plantar fasciitis pain location. It inserts on the fifth metatarsal base near the styloid, which must be distinguished from a zone 1 fifth metatarsal avulsion fracture on radiograph. In selective plantar fasciotomy for recalcitrant plantar fasciitis, the central cord is typically divided while the medial and lateral cords are preserved to maintain arch integrity and prevent pes planus.
Overuse injury of the lateral cord of the plantar fascia at its calcaneal origin produces lateral heel pain that is distinct in location from the typical medial plantar fasciitis, localised to the lateral calcaneal tuberosity; ultrasound confirms lateral cord thickening and targeted corticosteroid injection into the lateral cord provides relief.
