In combat sports, fighters often focus on aiming for the head to finish the fight. One effective alternative, however, is targeting the liver. The liver is an organ that sits in the right abdominal cavity, immediately behind the lowest ribs. While the ribcage does a good job of protecting many vital organs, the liver remains partially uncovered and exposed to attack. Traumatic impact to the liver, via punch, kick, or knee can be excruciatingly painful and is capable of incapacitating your opponent.
How can a liver strike cause this effect?
Vasovagal syncope. The vagus nerve innervates many vital organs and connects the parasympathetic nervous system, also known as the “rest and digest” system. Because the liver is one of the few organs left unprotected by the ribs, when it’s struck with a sufficient force, it unbalances the parasympathetic nervous system. When the system is stimulated in this way, it causes a cardioinhibitory (slows heart rate) and/or vasodepressor response (blood pressure drops). When this happens, there is reduced blood flow to the brain, which can cause fainting, confusion or temporary paralysis. People often describe this as feeling like their bodies turn off momentarily.
In boxing, a liver shot often occurs when an orthodox fighter throws a left hook to the body against an opponent with a staggered stance. In kickboxing or muay thai, this can also happen when a southpaw fighter throws a rear leg body kick or knee to an opponent with a mirror/open stance.
Many fighters focus their striking efforts on the head, but the body has many other weak points, like the liver, that can be effectively exploited to win the fight.