Second layer of muscles in the sole of the foot

Question 1

Quadratus plantae

Answer 1

Origin:

• Medial surface of calcaneus and lateral process of calcaneal tuberosity

Insertion:

• Lateral side of tendon of flexor digitorum longs in proximal sole of the foot

Innervation:

• Lateral plantar nerve from tibial nerve (S1, S2, S3)

Function:

• Assists flexor digitorum longus tendon in flexing toes II to V

Question 2

Lumbricals

Answer 2

Origin:

• First lumbrical - Medial dies of tendon of flexor digitorum longs associated with toe II;
• Second, third and fourth lumbricals - adjacent surfaces of adjacent tendons of flexor digitorum longus

Insertion:

• Medial free margins of extensor hoods of toes in II to V

Innervation:

• First lumbrical - Medial plantar nerve from the tibial nerve; second, third and fourth lumbricals - lateral plantar nerve from the tibial nerve (S2, S3)

Function:

• Flexion of metatarsophalangeal joint and extension of interphalangeal joints