Question

What's the difference between the brain's (sensory) relationship with outer toes vs with middle toes? How is this so?

Answer 1

Sensory innervation of the dorsum of the foot :

Sensory innervation of the dorsum of the foot is provided by the following four sets of nerves.

• Superficial peroneal nerve (musculocutaneous nerve)
• Deep peroneal nerve
• Sural nerve
• Saphenous nerve

The superficial peroneal nerve provides sensory innervation to the most of the dorsum of the foot except the the skin of the cleft between the first and second toes. It also supplies the the medial margin of the great toe.

The deep peroneal nerve provides innovation to the cleft between the first and second toes.

The sural nerve supplies the lateral margin of the dorsum of foot and lateral margin of the little toe.

The saphenous nerve supplies medial margins of the dorsum of the foot up to the head of the first metatarsal.

Sensory innervation of the dorsum of the foot :

The territories of the cutaneous nerves:

Sole of the foot :

The skin of the sole is thick and hairless. It is firmly bound to the underlying fascia by numerous fibrous bands. It is creased at the sites of skin movements. It contains large number of sweat glands. The skin over the major weight bearing areas of the sole- the heel lateral margin and the ball of the foot is very thick.

​​​​​​Cutaneous innervation of the sole of the foot :

The skin of sole of the foot is supplied by 3 cutaneous nerves which are arise from the tibial nerve directly or indirectly.

Areas supplied by three nerves roughly correspond to the three dermatomes of the sole.

• Medial calcaneal branches
• Cutaneous branches of the medial plantar nerve
• Cutaneous branches of the lateral plantar nerve

Medial calcaneal branches arise directly from the tibial nerve and supply the the skin over the posterior and medial portions of the sole-the weight bearing portion of the heal .It corresponds to the the dermatome S 1.

Cutaneous branches of the medial plantar nerve supplies the skin over the larger anteromedial portion of the sole and medial 3 and a half digits the corresponding dermatome is L 4.

Cutaneous branches of the lateral plantar nerve supply the skin over the smaller anterolateral portion of the sole and lateral one and a half digits. The corresponding dermatome is L 5.