Which sign is NOT a common indicator of a serious head injury?

Constricted pupils are not typically a common indicator of a serious head injury. In cases of significant head trauma, the more common pupil response is either dilated pupils or unequal pupil size, known as anisocoria. These changes are usually a sign of increased intracranial pressure or damage to the brain, which could affect the oculomotor nerve.

Conversely, combative behavior can signify altered mental status often seen in patients with severe head injuries, perhaps due to intracranial bleeding or swelling. CSF leakage from the ears is another serious indicator, as it may suggest a basilar skull fracture, which is a grave concern following head trauma. Decreased sensory function may indicate neurological deficits resulting from brain injury.

In summary, while all other options reflect significant potential issues associated with serious head injuries, constricted pupils typically do not align with the presentation of such conditions.