Muscles of the fourth layer of sole.

1. Plantar interossei-

• Origin- bases of third, fourth and fifth metatarsals.
• Insertion- bases of the proximal phalanges of third, fourth, fifth.
• Nerve supply- first and second by lateral plantar nerve, third by lateral plantar nerve.
• Actions- adductors of third, fourth and fifth, flexor of metatarsophalangeal and extensors of interphalangeal joint of third, fourth and fifth.

2. Dorsal Interossei-

• Origin- adjacent sides of metatarsal bones.
• Insertion- bases of proximal phalanges and dorsal expansion of toes.
• Nerve supply- first, second, third by lateral Plantar nerve, fourth by Superficial branch of lateral plantar nerve.
• Actions- abductor of toes from axis of second toe.