The Glasgow Coma Scale (GCS) is a clinical tool used to assess a person's level of consciousness after a brain injury. It evaluates three key areas: eye opening, verbal response, and motor response. Each area is scored, with a total score ranging from 3 to 15, where a lower score indicates a more severe impairment of consciousness. The GCS helps healthcare professionals quickly determine the severity of a patient's condition and guide treatment decisions. It is widely used in emergency medicine and critical care settings, providing a standardized way to communicate a patient's neurological status among medical teams.