The brainstem is a small but vital structure located at the base of the brain, connecting the cerebrum to the spinal cord. It consists of three main parts: the midbrain, pons, and medulla oblongata. Despite its small size (about three inches long), the brainstem controls many of the body's most essential automatic functions, including breathing, heart rate, blood pressure, swallowing, consciousness, and sleep-wake cycles.
A brainstem injury occurs when this critical structure is damaged through trauma, such as a severe blow to the head, rapid acceleration-deceleration forces, or penetrating injuries. These injuries are classified as traumatic brain injuries and are among the most serious types of head trauma. Brainstem damage can result from direct impact, rotational forces that cause shearing of nerve fibers, or secondary effects like swelling and bleeding that compress the brainstem.
The severity of brainstem injuries varies widely. Mild injuries may cause temporary symptoms like dizziness, nausea, or coordination problems. Moderate injuries can lead to prolonged unconsciousness, difficulty breathing, and significant neurological deficits. Severe brainstem injuries often result in coma, persistent vegetative state, or death. Because the brainstem controls so many vital functions, even relatively minor damage can have profound and lasting effects on a person's ability to function independently.