Damage to which area of the brain would result in weakness of the left arm and leg?

Damage to the right frontal cortex would lead to weakness on the left side of the body, including the left arm and leg, due to the way the brain's motor pathways are organized. The motor cortex is located in the frontal lobe and controls voluntary movements. Each hemisphere of the brain controls the opposite side of the body; thus, injury to the right side results in motor deficits on the left side.

The right frontal cortex is responsible for initiating movements and regulating motor activity for the left side of the body. If this area is damaged, the motor signals that travel down from the brain to facilitate movement in the left arm and leg are disrupted, leading to weakness or paralysis in those areas.

Understanding this lateralization of function is important in neuroanatomy and helps in diagnosing and managing conditions like stroke, where specific areas of the brain may be affected, resulting in characteristic patterns of weakness or functional deficits.