The acronym FOOSH is a widely recognized term in orthopedic and emergency medicine, used to describe a specific mechanism of injury. This term helps medical professionals quickly identify how an accident happened, suggesting a pattern of likely trauma to the upper body. Understanding this mechanism is the first step in recognizing and treating associated injuries that can affect the hand, wrist, forearm, elbow, and shoulder. FOOSH events are among the most common causes of upper extremity fractures, especially in children, older adults, and athletes.
Defining the Mechanism of Injury
FOOSH stands for “Fall Onto an Outstretched Hand,” referring to the instinctive reflex to extend an arm to brace for impact during a fall. This protective action immediately transfers the kinetic energy of the falling body up the arm, starting at the point of contact. The angle of impact typically forces the wrist into hyperextension, meaning it bends backward beyond its normal range of motion. This hyperextension transmits a massive compressive force through the small bones of the hand and wrist. The wrist is the first joint to absorb the blunt force, which determines the nature and severity of the resulting injury.
Common Wrist and Forearm Injuries
The most frequent injuries resulting from a FOOSH event occur at the wrist joint and the distal forearm. The radius, the larger of the two forearm bones, is particularly vulnerable to fracture just above the wrist joint. A Colles fracture is a specific break in the distal radius where the bone fragment is displaced backward and upward. This displacement can create a visible deformity in the wrist.
Another common break involves the scaphoid, one of the eight small carpal bones in the wrist. Scaphoid fractures are difficult to diagnose immediately because they may not show up on initial X-rays, often being mistaken for a simple wrist sprain. The scaphoid bone has a poor blood supply, meaning delayed treatment can lead to complications like non-union, where the bone fails to heal properly, or bone death. A fracture of the distal radius often occurs simultaneously with a break in the ulnar styloid, a small bony projection on the pinky-finger side of the wrist.
Injuries Affecting the Elbow and Shoulder
While the wrist is the primary site of injury, the force from a FOOSH can travel further up the kinetic chain, causing trauma to the elbow and shoulder, particularly in higher-energy falls. When the wrist and forearm absorb the initial impact less effectively, the energy is transmitted to the elbow joint. This can result in a radial head fracture, a break in the top part of the radius bone near the elbow. Severe force can also cause elbow dislocations, where the forearm bones are forced out of alignment with the humerus.
Further up the arm, the force may travel to the shoulder girdle, leading to more serious injuries. Common shoulder-related FOOSH injuries include fractures of the clavicle (collarbone) and shoulder dislocations. A shoulder dislocation occurs when the head of the humerus is forced out of the glenoid socket. This high-energy transfer can also separate the acromioclavicular (AC) joint, which connects the collarbone to the shoulder blade.