The wrist joint is made up of many bones. Any of the bones making up the wrist can fracture or break, such as in a fall or a sports injury. Orthopaedic surgeons like to categorize fractures by fracture type in order to help treat the condition and have a better idea about long-term prognosis.
Radius and Ulna
The radius and ulna bones are located in the forearm. They can break independently of one another or as part of a common fracture pattern. The Colles fracture is a fracture of the distal radius that results in the bones appearing like a dinner fork on x-ray. The fracture fragment displaces towards the top of the hand. The Colles fracture makes up 90 percent of distal radius fractures according to the "Handbook of Fractures."
The Smith fracture is the reverse of the Colles fracture. The fracture on x-ray looks like a "garden spade." The fracture fragment displaces towards the palm of the hand.
The radial styloid fracture occurs when the ligaments of the wrist are stretched and pull off a piece of the bone, the radial styloid. The ulnar styloid can be fractured in isolation or in combination with a distal radius fracture.
Proximal Carpal Bones
The proximal carpal bones are the scaphoid, lunate, triquetrum and the pisiform. The scaphoid bone is the most commonly fractures carpal bone according to the "AAOS Comprehensive Orthopaedic Review." Patients usually have pain at the base of the thumb. X-rays often appear normal initially. The scaphoid does not heal well and often requires surgery to repair the bone. The lunate, triquetrum and pisiform bones are less commonly fractured than the scaphoid. The triquetrum is the second most common carpal bone to be fractured.
Distal Carpal Bones
The distal carpal bones are the trapezoid, trapezium, capitate, and hamate. The trapezoid is uncommon to fracture especially in an isolation injury. The trapezium fracture is approximately 3 to 5 percent of carpal bone fractures according to the "Handbook of Fractures." The capitate bone is uncommon to fracture in isolation. It is relatively well protected in the distal carpal row of bones. The hamate bone can fracture either in the body of the bone or at its hook. Hamate fractures are not common. The hook of the hamate can be fractured in athletics when the palm of the hand is hit by an object. The ulnar and median nerves are located near the hook of the hamate and can be injured when the hamate is fractured.
References
- "AAOS Comprehensive Orthopaedic Review"; Dr. Jay Lieberman (ed); 2008.
- "Handbook of Fractures (3rd Ed)"; Dr. Kenneth Koval, Dr Joseph Zuckerman (eds); 2006.
