What type of brain injury did Alex suffer after a blow to the head?

A concussion is a type of brain injury that typically results from a blow to the head or a violent shaking of the head and body. It occurs when the brain is jolted inside the skull, leading to temporary disruption of brain function. Symptoms can include confusion, headaches, dizziness, and memory issues. The mechanism of injury—where a specific impact leads to a functional impairment without necessarily showing structural damage on imaging—characterizes concussions.

In contrast, a contusion involves actual bruising of brain tissue, which can be identified through imaging and often indicates a more severe injury. A fracture pertains to a break in the skull, which may accompany other injuries but is distinct from the functional disturbances seen in concussions. Whiplash primarily refers to soft tissue injuries of the neck, usually resulting from sudden acceleration-deceleration forces, and does not directly relate to brain injuries caused by a blow to the head. Thus, the identification of a concussion as the type of injury aligns with the description of Alex's situation following the impact.