A liver strike is one of the most painful and debilitating body shots a fighter can experience. The liver, a large vital organ in the upper right portion of the abdomen, is a highly vascular area responsible for a vast array of functions within the body. A sharp strike to the right side of the ribcage where the liver is located can be both excruciatingly painful and result in a momentary loss of breath, immediate fatigue, feeling of paralysis, or even complete loss of consciousness.
What’s the mechanism behind the often dramatic physiological response to a liver strike? The answer lies in the stimulation of the vagus nerve that occurs with a liver shot. The vagus nerve—Vagus meaning “wandering”—is actually two cranial nerves extending from the brainstem, traveling throughout the chest and abdomen, and connecting to the viscera, or organ systems. The vagus nerve both sends and receives signals from the body to the brain about the state of the body’s organs, and reacts to various stimuli accordingly. On its journey throughout the body, one of the organs that the vagus nerve and its associated nerve network innervate is, of course, the liver. Now, when the vagus nerve is stimulated, a variety of things happen.
During the initial force of a liver strike, the nerves in the area are impacted and undergo tiny chemical reactions with every electrical nerve impulse. With a hard enough hit, the chemical reactions in these nerves become unbalanced, and the resulting shock travels along the vagal nerve network. It takes time for the nerves to recover from this shock, which can result in a brief loss of breath or even a sensation of temporary paralysis. It’s like hitting your funny bone, but on a much larger scale. Additionally, more severe activation of the vagus nerve can cause a simultaneous cardioinhibitory and vasodepressive response, meaning a rapid drop in heart rate as well as a sharp drop in blood pressure. Most people experience a mixed response of the two, ultimately resulting in syncope, or fainting. The occurrence of vasovagal syncope is amplified by pain, high stress, and dehydration, all of which are commonly present in a fight setting. Enough damage to the vagus nerve can result in long-term vagal dysfunctions, such as irregular heartbeat, difficulty swallowing and breathing, and digestive disorders. However, if you’re lucky enough to endure a liver shot and still retain consciousness, don’t consider yourself off the hook. Blunt force to the livercan still result in crushing of blood vessels as well as liver lacerations or tears, causing internal bleeding. The structures in proximity to the liver, such as the pancreas and spleen, are subject to laceration and puncture. Rib fractures are also a concern. While a formidable tactic which will render your opponent senseless, being on the receiving end of a liver shotcan be cause for concern far beyond the loss of a single fight.