Which type of injury is caused by an external force contacting the head, placing the head in sudden motion?

• A. Deceleration injury
• B. Penetrating injury
• C. Acceleration injury
• D. Hemorrhagic injury

Answer: (C)

When an external force strikes the head and makes it undergo a rapid change in velocity, that is acceleration of the head. The brain, due to inertia, tends to stay in its previous state while the skull moves, creating shearing and stretching forces inside the brain tissue. This rapid forward or backward motion from the impulse is what defines acceleration injuries.

In contrast, a deceleration injury involves the head rapidly slowing down after moving forward, often with the brain continuing to move briefly inside the skull; a penetrating injury means an object breaches the skull and enters brain tissue; a hemorrhagic injury refers to bleeding within or around brain structures, which can occur with various trauma but isn’t defined by the head’s initial motion from an external impulse.