Concussion
From Memory Alpha, the free Star Trek reference.
A concussion is a common injury characterized by a loss of humanoid brain function as a result of a trauma. Whenever a humanoid feels dazed or is knocked unconscious after a blow to the head, he or she has had a concussion.
Commander Jonathan Archer suffered a concussion after being struck by a spatial anomaly in 2153, but made a complete recovery. (ENT: "Twilight")
In 2267, Chief Engineer Montgomery Scott was thrown against a bulkhead of the Enterprise causing a concussion for which he needed rest. (TOS: "Wolf in the Fold")
In 2373, Neelix was diagnosed with a concussion while trying to aid a Nezu planet being bombarded by asteroids. (VOY: "Rise")
