Which one of the following has maximum area of representation in the cerebral motor cortex?
First Metacarpophalangeal joint
Ans. D. First Metacarpophalangeal joint.
The primary motor cortex contains a detailed topographically organized map (motor homunculus) of the opposite body half, with the head represented most laterally, and the legs and feet represented on the medial surface of the hemisphere in the paracentral lobule. A striking feature is the disproportionate representation of body parts in relation to their physical size. Thus, large areas represent the muscles of the hand and face, which are capable of finely controlled or fractionated movements.