Final answer:
If a patient undergoes a head injury, it is possible that they have had a concussion.
Step-by-step explanation:
A concussion is a mild brain injury that can occur when a person experiences a strong blow to the head. It is characterized by a bruise on the surface of the brain and may cause temporary symptoms such as headache, drowsiness, and confusion. Most concussions in young people happen during sports, especially contact sports like football. Therefore, if a patient undergoes a head injury, it is possible that they have had a concussion.