Cause
The colloquial term “wrist fracture” is relatively vague, and is therefore more precisely subdivided into the various fracture types in medical terminology. These are based on the injury pattern and the location of the injury. The most common fracture of the wrist is the Colles fracture after a frontal fall onto the hand.
It occurs very often in skateboarders, snowboarders and elderly people. The underlying injury mechanism is that the entire weight of the upper body and arms is applied to the outstretched palm with a swing. The most unstable point between upper body and palm is the connection between ulna, radius and carpal bone – i.e. the proximal wrist.
It is usually the first to break when a strong force is applied in this area. On the other hand, there is the much rarer Smith’s fracture after falling onto the angled hand (so-called flexion fracture). It is preceded by a fall on the back of the hand.
Since a natural defensive movement when falling forward is the extension of the hands and arms, this injury is relatively uncommon. Expressed in figures, 80% of all fractures of the wrist are extension fractures, and only 20% are flexion fractures. The two fracture types mentioned above, the Colles fracture and the Smith fracture, are fractures of the proximal wrist.
They are also referred to as distal radius fractures, since the fracture does not actually occur on the hand, but in the part of the radius near the hand. However, since ulna, radius and carpal bone together form a part of the wrist (namely the proximal part), they are also called wrist fractures. To make things a little more complicated, the distal radius fracture can be further subdivided into extra-articular, partial and complete joint fractures.
The extent to which the proximal wrist is affected and the degree of fracture is indicated. While Colles and Smith fractures are the two most important fractures of the proximal wrist, a distal wrist fracture is much less common.This is a bone fracture (or several) on the lower palm of the hand. If you look at the palm of the hand, you will find the carpal bones in the area of the ball of the hand – however, the carpal bones do not take up the entire palm of the hand!
Approximately at the height of the thumb, the metacarpals are already attached. There are eight carpal bones in the hand. Each of these bones can fracture, but the mechanisms behind them are not very specific.
They usually occur as accompanying fractures in a Colles or Smith fracture when the force applied to the palm was too strong. Since each of the carpal bones has a proper name, they are called scaphoid fractures or scaphoid fractures, depending on which bone is broken. Between the individual carpal bones there are still joints that can be damaged when the bone is broken.
Other causes of a fracture of the wrist, apart from a fall, are generally age and the associated osteoporosis. With increasing age, the bone density and thus the resilience of the bone decreases significantly. As a result, bones become more unstable and break more easily.
The risk of falling also increases with reduced mobility and impaired vision and hearing. Moreover, overweight patients put particular strain on their bones: On the one hand, their bones are subject to increased weight at all times. On the other hand, in the event of a fall, the increased weight generates a significantly higher force on the wrist and thus promotes fracture.
