A concussion can be thought of as a brain bruise. A concussion is any bump to the head can cause the brain to run into the skull. While many of the bumps to the head do not give symptoms, they are still concussions. Concussions disrupt normal brain functions and can cause many lingering symptoms.
Look in the Symptoms page to find out more about the symptoms that a concussion can cause.
Look in the Consequences of Concussions page to find out more about conditions resulting from multiple concussions over time.
"Concussion, from the Latin concutere ("to shake violently") or the Latin concussus ("action of striking together"), is the most common type of traumatic brain injury."
From Merriam-Webster's Medical Dictionary:
1 : a hard blow or collision
2 : a condition resulting from the stunning, damaging, or shattering effects of a hard blow
especially : a jarring injury of the brain resulting in disturbance of cerebral function and sometimes marked by permanent damage
con·cus·sive Pronunciation: /-ˈkəs-iv/