What structure is primarily affected in a coup-contrecoup brain injury?

A coup-contrecoup brain injury primarily affects the cerebrum, which is the largest part of the brain responsible for many higher functions, including voluntary movement, sensory perception, language, and reasoning. This type of injury occurs when a forceful impact to the head causes the brain to collide with the inside of the skull at the site of impact, known as the coup. Subsequently, the brain can also rebound and strike the opposite side of the skull, resulting in the contrecoup injury.

The cerebrum is particularly vulnerable in this scenario because it occupies the largest volume within the cranial cavity, making it susceptible to trauma caused by sudden deceleration or acceleration. Although other brain structures can be affected in various types of head injuries, the coup-contrecoup mechanism specifically relates to the dynamics and impacts experienced by the cerebrum during such traumatic events.