Which components are affected in a head injury?

A head injury primarily impacts the scalp, skull, and brain due to their integral roles in protecting and supporting brain function. The scalp, being the outer layer, can sustain injuries such as lacerations or abrasions, which may also lead to bleeding. The skull serves as a bony protective barrier for the brain and can fracture upon impact, potentially leading to brain injury or hemorrhage. Inside the skull, the brain is the most critical component affected, as trauma can lead to contusions, concussions, or more severe injuries like traumatic brain injury (TBI) that can have immediate and long-term effects.

The other answer choices cover areas that are not the main focus of head injuries. While the spine, neck, and extremities can sustain injuries in a fall or blunt trauma, they are not directly affected by the mechanisms leading to head injuries. Skin, muscle, and joints can be involved in various types of trauma but are not specifically impacted in the context of a head injury per se. Also, although the eyes, ears, and nose might experience secondary effects from head injuries, they are not the primary components that are directly affected by a traumatic head injury itself. Thus, the most accurate choice reflecting the components affected is indeed the scalp,