The phenomenon of people raising or flexing their arms in their final moments is an involuntary physiological response often observed during catastrophic brain injury or oxygen deprivation. This movement, sometimes called the “dying salute,” is not a conscious action or a sign of pain, but a reflex indicating profound neurological distress. It represents the body’s physical reaction when the brain’s control centers cease to function normally, triggering ancient motor pathways. The action is a temporary sign of extreme physiological imbalance, where muscles receive uninhibited signals from lower brain structures.
Oxygen Deprivation and Brain Response
The process begins with a severe lack of oxygen (hypoxia) or a critical loss of blood flow (ischemia) to the brain. Brain tissue is uniquely sensitive to oxygen deprivation, requiring a constant supply to maintain its complex operations. When this supply is interrupted, such as during cardiac arrest, major stroke, or severe trauma, the brain begins to fail within minutes.
The brain’s higher-level functions, which reside in the cerebral cortex and govern conscious thought and voluntary movement, are the first to be compromised. These areas are metabolically demanding and rapidly lose function when oxygen levels drop precipitously. This loss of function effectively silences the inhibitory signals the cortex normally sends to the lower, more primitive parts of the brain.
As the sophisticated control of the cortex fades, the brainstem, which handles automatic functions like breathing and basic motor reflexes, effectively takes over. This shift in control hierarchy is the trigger for the involuntary movements. The brainstem’s motor pathways, now unchecked by the cortex, begin to fire without regulation. This unregulated firing is the root cause of the abnormal muscle rigidity and posturing that follows.
Involuntary Muscle Contraction and Neurological Posturing
The specific movement of the arms raising or flexing inward is a manifestation of a distinct neurological reflex known as decorticate posturing. This posturing occurs when there is damage to the corticospinal tract, a major pathway that carries motor information from the cortex down to the spinal cord. When this pathway is injured above the red nucleus in the midbrain, the balance of motor signals is disrupted.
In decorticate posturing, the muscles that cause the arms to flex or bend are effectively released from inhibition, causing them to contract strongly and involutarily. This results in the arms bending at the elbows, drawing them up toward the chest, and causing the wrists and fingers to flex. Simultaneously, the legs stiffen and extend, often with the feet turning inward. This combination of upper-body flexion and lower-body extension creates the characteristic posture.
A less common, but more severe, presentation is decerebrate posturing, which involves damage lower in the brainstem. In this case, the motor signals cause the arms to extend rigidly and turn outward, along with the legs. While both are involuntary reflexes, the inward flexing of the arms seen in decorticate posturing is often the movement people associate with the “dying salute.” These movements are driven by the uncontrolled activity of motor centers in the brainstem, and are not an expression of conscious experience.
Contexts Where Terminal Movement is Observed
This involuntary motor response is a clinical sign of severe neurological injury and is often witnessed in specific medical scenarios where brain perfusion is catastrophically compromised. The posturing is frequently observed following major traumatic brain injuries that result in swelling or bleeding, which rapidly increases pressure inside the skull. The increased pressure can compress and damage the brain’s motor pathways.
Severe anoxic brain injury, caused by events like prolonged cardiac arrest, suffocation, or near-drowning, can also trigger this reflex due to the widespread oxygen deprivation. The movement serves as a stark indicator of the degree of distress and damage the brain is undergoing. It is a transient sign that may occur as a patient’s condition rapidly deteriorates.
In some extreme instances, a similar phenomenon called the Lazarus sign, where a brain-dead patient briefly raises their arms and crosses them over the chest, can be observed. This is a spinal cord reflex and not a sign of returning consciousness, highlighting that the spinal cord can act independently of the brain.