Parents often worry about a toddler dislocating a wrist following a sudden tug or pull on the arm. While the wrist is a complex joint, a true dislocation of the carpal bones is uncommon in this age group. A related, yet distinct, injury is far more likely when a sudden, longitudinal force is applied to the arm. This common injury involves a partial dislocation within the elbow joint, often mistakenly attributed to the wrist by caregivers.
Understanding Traction Injuries: Wrist vs. Elbow
The anatomical difference between a toddler and an adult explains why the elbow is the vulnerable point under traction. A toddler’s ligaments, the fibrous tissues connecting bones, are comparatively lax and less developed than those in older children. The injury resulting from pulling on a child’s arm is called Radial Head Subluxation, commonly known as Nursemaid’s Elbow.
This subluxation occurs when the radius, one of the two forearm bones, partially slips out of alignment at the elbow. The annular ligament, which acts like a sling holding the radial head in place, slips over the small, underdeveloped head of the radius. The ligament then becomes temporarily trapped between the radial head and the humerus, causing sudden pain and immobility. This mechanism is almost exclusively seen in children between the ages of one and four, before their bones and ligaments mature and strengthen.
Common Scenarios That Cause the Injury
The injury is almost always caused by a sudden, axial pull on the forearm or hand during routine daily activities. A common scenario involves an adult or older sibling swiftly pulling a toddler upward by one arm, such as lifting them over a curb or up a step. This vertical traction creates the force necessary to slip the ligament out of position.
Another frequent cause is attempting to prevent a fall by quickly grabbing the child’s hand or wrist, which creates a sudden jerk along the arm. Playfully swinging a toddler by the hands or forcefully pulling an arm through a tight jacket sleeve can also generate the necessary force for the subluxation. These incidents are typically accidental, and the small amount of force required often makes the injury seem disproportionate to the event.
Identifying the Symptoms
The primary sign of Radial Head Subluxation is the child’s sudden and complete refusal to use the affected arm. Immediately after the injury, the child often cries out in pain but quickly settles into a protective posture. They typically hold the arm motionless against their body, often with the elbow slightly bent and the palm turned downward, a position known as pronation.
The child allows the arm to be supported or moved at the shoulder, but any attempt to move the elbow or turn the forearm will elicit a painful response. A distinguishing feature of this injury is the lack of obvious physical signs like swelling, bruising, or visible deformity around the elbow joint. If the child displays significant swelling or a clear deformity, a more serious injury like a fracture should be suspected, requiring immediate medical evaluation.
Seeking Treatment and Reduction
The immediate action for a suspected Nursemaid’s Elbow is to remain calm and seek professional medical attention at an urgent care facility or emergency room. Parents should avoid any temptation to shake, pull, or forcefully move the arm, as attempting to relocate the joint without proper training can cause further injury. The doctor will diagnose the injury based primarily on the history of the event and the characteristic way the child holds the arm.
In cases where the history is unclear or if a fall was involved, an X-ray may be taken first to rule out a fracture of the bones. The definitive treatment is a gentle, specialized maneuver called a closed reduction, performed by the physician without the need for anesthesia or sedation. The doctor will use a technique that involves specific movements, such as hyperpronation or a supination-flexion motion, to gently slip the annular ligament back over the radial head. A faint click or pop may be heard or felt as the ligament returns to its correct position. This procedure is quick, lasting only a few seconds, and often results in immediate relief, with most children regaining full use of the arm within minutes.