Which muscle is NOT located in the 1st plantar layer?

Which muscle is NOT located in the 1st plantar layer?

• A. Abductor hallucis
• B. Flexor digitorum brevis
• C. Abductor digiti minimi
• D. Quadratus plantae

Answer: (D)

The idea here is understanding how the intrinsic muscles of the sole are organized into plantar layers. In the first plantar layer, the muscles you see are Abductor hallucis medially, Flexor digitorum brevis in the middle, and Abductor digiti minimi laterally. They’re superficial and sit close to the plantar surface. Quadratus plantae, however, sits deeper in the sole and belongs to the second plantar layer, together with the deep flexor tendons and the lumbricals. Its main job is to assist the flexor digitorum longus by guiding its pull as the toes flex, especially helping with toe flexion for the lateral toes. Because of its depth and position, it’s not part of the first layer. So the muscle not located in the first plantar layer is Quadratus plantae.

The idea here is understanding how the intrinsic muscles of the sole are organized into plantar layers. In the first plantar layer, the muscles you see are Abductor hallucis medially, Flexor digitorum brevis in the middle, and Abductor digiti minimi laterally. They’re superficial and sit close to the plantar surface.

Quadratus plantae, however, sits deeper in the sole and belongs to the second plantar layer, together with the deep flexor tendons and the lumbricals. Its main job is to assist the flexor digitorum longus by guiding its pull as the toes flex, especially helping with toe flexion for the lateral toes. Because of its depth and position, it’s not part of the first layer.

So the muscle not located in the first plantar layer is Quadratus plantae.