Layers of the sole of the foot

Question 1

First layer (superficial)

Answer 1

Medial to lateral:
Abductor hallucis
Flexor digitorum brevis
Abductor digiti minimi

Immediately deep to plantar aponeurosis

Question 2

Second layer

Answer 2

Flexor digitorum longus tendons 
Quadratus plantae (most lateral) - 2 heads 
Lumbricals - attach to the tendons of the flexor digitorum longus

Question 3

Third layer

Answer 3

Flexor hallucis brevis
Adductor hallucis - oblique head can be seen more easily
Flexor digiti minimi

Question 4

Fourth layer (deep)

Answer 4

Doral interossei

Plantar interossei