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502 SecTioN iii Neurology aNd Special SeNSeS ` neurology—AnAtomy And Physiology Neurology aNd Special SeNSeS ` neurology—AnAtomy And Physiology

Homunculus Topographic representation of motor and sensory areas in the cerebral cortex. Distorted appearance
is due to certain body regions being more richly innervated and thus having  cortical
representation.

Motor homunculus Sensory homunculus

Anterior
cerebral Hip Knee Hip Trunk
artery Trunk Leg Neck Head
Middle Wrist Elbow Ankle Foot Shoulder Arm Elbow Forearm
cerebral Little Toes Wrist Little
Shoulder
Hand
artery Ring Toes Ring
Genitals Fingers Middle
Index
Middle
Posterior Thumb Fingers Thumb
Index
cerebral Neck
artery Brow Eye
Nose
Eyelid & eyeball
Face
Lips
Upper lip
Jaw
Tongue
Lower lip
Teeth, gums
Swallowing Intra-abdominal Tongue
Pharynx
Cerebral arteries—cortical distribution

Anterior cerebral artery (supplies anteromedial surface)
Middle cerebral artery (supplies lateral surface)
Anterior
Posterior cerebral artery (supplies posterior and inferior surfaces)

Anterior

Posterior
Posterior
Watershed zones Cortical border zones occur between anterior Infarct due to severe hypoperfusion Ž proximal
and middle cerebral arteries and posterior and upper and lower extremity weakness (“man-
A
middle cerebral arteries (blue areas in A ). in-the-barrel syndrome”), higher order visual
Internal border zones occur between the dysfunction (if posterior cerebral/middle
superficial and deep vascular territories of the cerebral cortical border zone stroke).
middle cerebral artery (red areas in A ).

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