Quadratus Plantae Muscle

Origin

The quadratus plantae muscle consists of two heads:

- a large medial head, which originates from the medial aspect of the plantar surface of calcaneus;

- a small lateral head, which originates from the area of the lateral aspect of the plantar surface of calcaneus that is located anterior to the lateral process of calcaneus.

Insertion

The muscle bellies of the medial and lateral heads of quadratus plantae travel inferiorly and converge to a tendon. The tendon inserts onto the tendon of the flexor digitorum longus muscle at the part where it divides into its four tendons.

Key Features & Anatomical Relations

The quadratus plantae muscle is located in the second layer of muscles that are found in the plantar part of the foot. It is a short, broad, quadrilateral type of skeletal muscle.

It is located:

- superficial (inferior) to the calcaneus and cuboid bone, and the long plantar ligament;

- deep (superior) to the flexor digitorum brevis muscle, the abductor digiti minimi muscle of foot, lateral plantar vessels, and the lateral plantar nerve;

- lateral to the abductor hallucis muscle and the tendon of the flexor hallucis longus muscle.

Actions

The quadratus plantae muscle is involved in multiple actions, which it exerts by pulling on the tendons of the flexor digitorum longus muscle:

- assists in flexion of the distal phalanges at the distal interphalangeal joints of the second, third, fourth and little toes;

- assists in flexion of the middle phalanges at the proximal interphalangeal joints of the same toes;

- assists in flexion of the proximal phalanges at the metatarsophalangeal joints of the same toes (Standring, 2016).

References

Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41st edn.: Elsevier Limited.