Nursemaid elbow is a common and easily-treated condition.
Correct diagnosis is the primary challenge to the physician.
The etiology is slippage of the head of the radius under the annular ligament. The distal attachment of the annular ligament covering the radial head is weaker in children than in adults, allowing it to be more easily torn. The oval shape of the proximal radius in cross-section contributes to this condition by offering a more acute angle posteriorly and laterally, with less resistance to slippage of the ligament when axial traction is applied to the extended and pronated forearm. The common belief that nursemaid elbow is due to children having a radial head smaller than the radial neck is incorrect. Published case series report a slight left arm predominance in both males and females.