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. Nursemaid elbow most commonly occurs in 1-4 year old children. However, it has been reported in patients as young as 4 months and as old as 15 years.
Diagnosis is made primarily by history.
Parents often give a history of a young child with no history of trauma who suddenly refuses to use an arm. A history of axial traction by a pull on the hand or wrist may be elicited, but often is not volunteered. A toddler is pulled by the wrist up and over an obstacle. An arm is pulled through the sleeve of a sweater or coat. The condition tends to be unilateral.