Presentation
Right plantar foot pain at 5th metatarsal base region for the last few weeks. No trauma.
Patient Data
There is a band-like structure extending from the lateral tubercle of the calcaneum to the plantar and lateral side of the 5th metatarsal base. It is the lateral cord of the plantar fascia. There is thickening and hypoechogenicity at its distal insertion at the 5th metatarsal base which correlates with the site of pain. There is no tear.
Peroneus brevis insertion to the 5th metatarsal base is normal without changes of tendinosis/tear. Peroneus longus tendon is normal near 5th metatarsal base.
The central cord of the plantar fascia was normal( images not uploaded).
Case Discussion
The plantar fascia has three cords namely central, lateral and medial. The proximal third of the central cord is most commonly involved in plantar fasciitis3.
The case shows plantar fasciitis of the lateral cord which is an uncommon location. It involves the distal end of the fascia at its attachment to the 5th metatarsal base1. The patient presents with localized pain in the plantar-lateral foot region. The distal attachment of the lateral cord is on the lateral-plantar side of the 5th metatarsal base whereas attachment of the peroneus brevis is more towards the lateral-dorsal side.
The ultrasound findings of plantar fasciitis are like any other tendinosis; namely hypoechoic thickening, loss of fibrillar echotexture, and loss of fascial edge sharpness3.