1st and 2nd plantar layers of the foot (Latin)

The mm. Plantares mediales/laterales/centrales can be alternatively classified according to four muscular layers (strata). The stratum primum (left) and secundum (right) can be identified in this image. The stratum primum is composed of three muscles: the m, abductor hallucis (medial), m. flexor digitorum brevis (central) and m. abductor digiti minimi (lateral). All three extend distally from the tuber calcanei to the toes and contribute to the maintenance of the concavity of the foot. The stratum secundum consists of the m. quadratus plantae and the four mm. lumbricales which both belong to the mm. centrales pedis. Tendons of the m. flexor hallucis longus and m. flexor digitorum longus run within the same plane as these muscles. The m. quadratus plantae arises by a caput medialis/lateralis from the calcaneus and inserts onto the lateral aspect of the tendon of the m. flexor digitorum longus as it passes through this region. The four mm. lumbricales arise from the tendons of the m. flexor digitorum longus, at their angles of separation, and insert onto the medial aspect of the aponeurosis extensoria digitorum 2-5.