What is a coup/contrecoup injury?

• A. Damage at the site of impact and opposite side from external forces
• B. Shearing injury to white matter
• C. Bleeding within the ventricles
• D. Global brain swelling without focal injury

Answer: (A)

Coup-contrecoup injuries come from the brain’s inertia during rapid head movement. When the head is struck, the brain hits the skull at the point of impact (coup) and, as it continues to move, slams into the opposite skull surface (contrecoup). This creates two focal injuries: one at the impact site and one on the opposite side. That pattern—damage both at the impact site and on the opposite side—is what defines coup/contrecoup.

This is distinct from other injury patterns: a diffuse axonal injury involves widespread shearing of white matter rather than two focal contusions; intraventricular bleeding is bleeding into the brain’s ventricular system; global brain swelling without focal injury describes generalized edema without discrete contusions. Thus, the best description of coup/contrecoup injury is damage at the site of impact and on the opposite side from the external force.