72 Neuroanatomy: Draw It to Know It
Know-It Points
Sensory Map of the Hand
■ Th e median nerve covers the ball of the thumb, the
lateral palm, and the palmar surface and dorsal tips of
the lateral digits.
■ Th e ulnar nerve covers the palmar and dorsal surfaces
of the medial one third of the hand and digits.
■ Th e radial nerve covers the dorsal lateral two thirds of
the hand and proximal dorsal surface of the lateral
d i g i t s.Sensory Map of the Foot
■ Tibial nerve branches cover the plantar foot.
■ Peroneal nerve branches cover the dorsal foot.
■ Th e plantar nerves cover the plantar foot and the
medial calcaneal nerve covers the heel.
■ Th e superfi cial peroneal nerve covers the dorsum
of the foot, except that the deep peroneal nerve
covers the webbing between the great toe and second
digit and except for the distal sural branches.
■ Th e distal branches of the sural nerve cover the lateral
malleolus, lateral foot, and little toe.
■ Th e saphenous nerve covers the instep of the foot.Dermatomes
■ C7 covers the middle fi nger, C8 the medial hand,
C6 the lateral hand and lateral forearm, C5 the
upper lateral arm, T1 the medial forearm, and
T2 the medial upper arm.
■ T4 covers the nipple line and T10 the umbilicus.
■ L3 and L4 cover the knee, L5 covers the great toe,
and S1 covers the ankle and little toe.
■ Th e coccyx covers the center of the anus; S5 through
S1 form rings around it.
■ S2 covers the posteromedial lower limb and S1 covers
the posterolateral lower limb.
■ C2 covers the back of the head.Cutaneous Nerves — Upper Limb
■ Th e medial and lateral cutaneous nerves of the
forearm and arm cover the medial and lateral forearm
and arm, respectively.
■ Th e intercostobrachial nerve covers the axilla.
■ Th e supraclavicular nerve covers the shoulder.
■ Th e posterior cutaneous nerves to the forearm and
arm cover the midline posterior forearm and arm,
r e s p e c t i v e l y.Cutaneous Nerves — Lower Limb
■ Th e lateral femoral cutaneous nerve covers the
lateral thigh, the posterior femoral cutaneous nerve
covers the posterior thigh, and the anterior femoral
cutaneous nerve covers the anterior and medial
thigh.
■ Th e lateral sural cutaneous nerve and the superfi cial
peroneal nerve cover the upper lateral and lower
lateral leg , respectively.
■ Th e sural nerve covers the posterior leg.
■ Th e saphenous nerve covers the medial leg.