If you do not use proper hand alignment when punching, you are exposing yourself to injury. The most common injury is what is known as “boxer’s fracture,” which is a fracture of the long bone that runs across the top of the hand (metacarpal) and/or the knuckle. This fracture usually occurs on the bones of the last two fingers. The top of the hand is not well supported for the transmission of force because it connects to other bones of the wrist at an oblique angle. Other common injuries include the fracture of the wrist and/or the elbow.
Boxer's fracture is not just a novice injury. Novice students usually cannot generate enough punching force to cause the fracture, so most boxer's fractures occur in experienced students who let their technique slip and fail to maintain proper hand alignment. Turning the hand so that the last two knuckles strike first is the most common cause of a boxer’s fracture. Another problem is that people do not align their entire wrist correctly when doing the basic fore fist punch. If the wrist is bent or bends during contact, injury to the wrist can occur. Another problem is that people do not align their entire wrist correctly when doing the basic fore fist punch. If the wrist is bent or bends during contact, injury to the wrist can occur.
There is a solid bone-to-bone straight line connection from the knuckles of the first and index fingers through the long bones (metacarpals) of the hand into the wrist and up the forearm. This means that when the arm is extended in a punch, all the bones from the first two knuckles to the shoulder are aligned in basically a straight line. This alignment permits the impact of a punch to be absorbed by the body. However, the metacarpal bones of the last two knuckles meet the wrist at an oblique angle, which prevents the transmission of forces along the arm and leads to a fracture. Allowing the elbow to flare outward during a straight punch (instead of staying behind the fist) causes the last two knuckles to strike first, which leads to fractures.
Boxer’s tape their hands into the proper position so that striking forces are properly aligned. The fixed wrist also keeps hook punches in tight and prevents the use of a large hooking punch. Since boxers rely on this artificial means of keeping the wrist aligned, they have not learned how to do so themselves. Therefore, in fights out of the ring, they are susceptible damaging their hands.