Concussion

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. 

In 2267, Chief Engineer Montgomery Scott was thrown against a bulkhead of the USS Enterprise (NCC-1701), causing a concussion for which he needed rest. 

According to Doctor Julian Bashir, the illusionary Jadzia Dax had a "nasty concussion" after she knocked her head on a console. 

In 2373, Arridor and Kol dealt Ensign Murphy a blow that left him with a severe concussion. 

Later that year, Neelix was diagnosed with a concussion while trying to aid a Nezu planet being bombarded by asteroids.