Today Zeke came home from daycare complaining that his arm hurt, and he was reluctant to use it for anything. On the pediatrician's advice, we took him to the emergency room in case an X-ray was needed. Turns out it was nursemaid's elbow.
A child should not be lifted or swung by the arms or hands nor should a child's arm be pulled hard. A small child should be lifted from under the arms.
... [N]ursemaid's elbow commonly occurs when an obstinate child is forcibly pulled along or lifted by the forearm by a parent or older sibling. For example, the injury might occur in a shopping center where a young child, typically two or three years old, is intent on pursuing a course or selecting an item somewhat different from the intentions of the parent.
And there you are. He was back to normal in about five minutes and within an hour he was telling people about how he hurt his arm and had to go to the hospital "yesterday."