Final answer:
The primary motor cortex is situated in the precentral gyrus of the frontal lobe, playing a key role in initiating and planning movements.
Step-by-step explanation:
The primary motor cortex is located in the precentral gyrus of the frontal lobe. This region of the brain directly connects to cranial and spinal motor neurons and is responsible for initiating movement. Neurosurgeon Walter Penfield contributed significantly to our understanding of the motor cortex, which plays a crucial role in planning movement and stimulating skeletal muscle contraction through the spinal cord neurons.