Quadratus plantae

The quadratus plantae (Latin: musculus quadratus plantae), also known as the flexor accessorius, is a rectangular-shaped muscle of the sole that stretches between the calcaneus and flexor digitorum longus tendon. It belongs to the central compartment (middle group) of the plantar foot muscles. The quadratus plantae is one of the muscles that aid in the flexion of the toes.

Origin

The quadratus plantae muscle has two heads - lateral and medial - separated by the lateral plantar ligament. The lateral head originates from the lateral process of the calcaneal tuberosity, while the medial head arises from the medial surface of the calcaneus.

Insertion

The quadratus plantae inserts into the tendon of the flexor digitorum longus muscle.

Action

The quadratus plantae muscle provides toe flexion at the second to fifth metatarsophalangeal joints.

Innervation

The quadratus plantae is innervated by the lateral plantar nerve (S2 - S3) - one of the terminal branches of the tibial nerve.

Blood suppy

The quadratus plantae receives arterial blood supply from the medial and lateral plantar arteries. Both are branches of the posterior tibial artery.