The shoulder complex is a highly mobile ball-and-socket joint, which makes it uniquely susceptible to injury from sudden trauma. This mobility sacrifices stability, allowing the force from a fall to easily disrupt the intricate network of bones, ligaments, and soft tissues. Landing directly on the side of the shoulder or bracing oneself by falling onto an outstretched hand (a common FOOSH injury) transfers significant energy to the joint. This impact can result in a wide spectrum of damage, ranging from simple sprains to complex fractures and dislocations.
Bone Fractures
Fractures are a serious concern following a hard fall, often involving the clavicle (collarbone) or the proximal humerus (the upper part of the arm bone). A clavicle fracture typically results from landing directly on the shoulder or transmitting force up a straightened arm. These breaks constitute about five percent of all adult fractures and present with sharp pain, bruising, and sometimes a noticeable bump where the bone tents the skin.
Fractures of the proximal humerus, the section closest to the shoulder joint, are common in older adults, especially those with reduced bone density due to osteoporosis. This injury usually occurs from a fall onto an outstretched hand, where the force travels up the arm and impacts the humeral head. The severity is determined by the number of fragments and their displacement, sometimes requiring surgery to fix the pieces with plates and screws. For both fracture types, movement is severely limited.
Joint Separations and Dislocations
Beyond broken bones, the force of a fall can force the shoulder’s bony components out of alignment. It is important to distinguish between a shoulder separation and a shoulder dislocation, as they involve different joints.
A shoulder separation is an Acromioclavicular (AC) joint injury, occurring where the collarbone meets the highest point of the shoulder blade (the acromion). This injury is a sprain or tear of the connecting ligaments, typically happening when a person falls directly onto the tip of the shoulder. Separations are graded based on the severity of the ligament tear and the resulting displacement of the collarbone, which can lead to a visible bump on the top of the shoulder.
A true shoulder dislocation affects the main shoulder joint, the Glenohumeral (GH) joint, where the ball of the upper arm bone pops entirely out of the shallow socket. A glenohumeral dislocation is generally more severe than a separation, often occurring when the arm is extended during the fall. This displacement stretches or tears the joint capsule and stabilizing ligaments. Dislocation requires urgent medical attention to manually reposition the bone, as the trauma can also damage adjacent soft tissues, nerves, or blood vessels.
Soft Tissue Damage
The fall’s energy can also cause damage to non-bony structures, including the muscles, tendons, and cartilage that provide stability and smooth motion.
Rotator Cuff Tears
The rotator cuff is a group of four muscles and their tendons that surround the shoulder joint, helping to keep the humerus centralized in the socket. A fall, particularly one where the arm is wrenched or stretched, can cause a partial or full tear in one or more of these tendons. A rotator cuff tear results in pain, weakness, and a limited ability to lift or rotate the arm, particularly overhead.
Labral Tears
Another common soft tissue injury is a labral tear, which involves damage to the labrum, a ring of specialized cartilage lining the rim of the shoulder socket. The labrum deepens the socket, enhancing stability. It can be torn when the arm is pulled violently or when the shoulder dislocates, as the humeral head scrapes against the rim. Symptoms often include a catching, clicking, or popping sensation within the joint, along with instability.
Immediate Actions After a Fall
Immediately following a fall onto the shoulder, remain still and assess the extent of the injury. If there is an obvious deformity, profound weakness, or an inability to move the arm, urgent medical care is necessary, as this suggests a fracture or dislocation. For less severe initial pain, first-aid steps can be taken while arranging for a professional medical evaluation.
The RICE protocol (Rest, Ice, Compression, and Elevation) is the standard initial approach for acute injuries to manage pain and swelling. Rest means avoiding painful movement; a sling can be used to immobilize the arm. Applying ice packs for 15 to 20 minutes helps reduce local inflammation and numb the pain. While compression and elevation are less practical for the shoulder than an extremity, keeping the arm supported and applying ice provides immediate relief.