Lumbrical (1-4) is located in which plantar layer?

Lumbrical (1-4) is located in which plantar layer?

• A. 2nd layer
• B. 1st layer
• C. 3rd layer
• D. Dorsum

Answer: (A)

In the sole of the foot, the lumbrical muscles belong to the second plantar layer. This layer houses the tendons of flexor digitorum longus along with the lumbricals and the quadratus plantae, all of which work together to control toe flexion and toe alignment. The lumbricals originate from the flexor digitorum longus tendons and insert into the sides of the extensor expansions of toes, enabling flexion at the metatarsophalangeal joints while aiding extension at the interphalangeal joints. Knowing the other layers helps situate them: the first layer includes the abductor hallucis, flexor digitorum brevis, and abductor digiti minimi; the third layer has the flexor hallucis brevis, adductor hallucis, and flexor digiti minimi brevis; the fourth layer contains the plantar and dorsal interossei. The dorsum is the top surface, not a plantar layer.

In the sole of the foot, the lumbrical muscles belong to the second plantar layer. This layer houses the tendons of flexor digitorum longus along with the lumbricals and the quadratus plantae, all of which work together to control toe flexion and toe alignment. The lumbricals originate from the flexor digitorum longus tendons and insert into the sides of the extensor expansions of toes, enabling flexion at the metatarsophalangeal joints while aiding extension at the interphalangeal joints.

Knowing the other layers helps situate them: the first layer includes the abductor hallucis, flexor digitorum brevis, and abductor digiti minimi; the third layer has the flexor hallucis brevis, adductor hallucis, and flexor digiti minimi brevis; the fourth layer contains the plantar and dorsal interossei. The dorsum is the top surface, not a plantar layer.