The deltoid tuberosity--a potential pitfall (the "delta sign") in bone-scan interpretation: concise communication.

Evaluation of 100 consecutive technetium methylene diphosphonate bone scintiscans revealed, in seven patients, increased uptake in the upper third of the humeral shaft. Comparison with the radiographs revealed that this corresponded to the presence of a prominent deltoid tuberosity. Though this uptake (the delta sign) is not a common finding, its recognition is important to prevent bone-scan misinterpretations.