Retrospective review of 30 patients with nonunion of the humeral shaft treated from 1984–1999 revealed nine patients with an initial fracture pattern which to our knowledge was not described previously. Humeral fractures originated at the junction of the proximal and middle thirds of the diaphysis as an hemitransverse medial fracture that extended with a great lateral butterfly third fragment with its distal portion long and sharp. The patients were women approximately 60 years old. Eight fractures progressed to nonunion after initial conservative treatment. All fractures followed the same pattern: the proximal humeral fragment healed with the proximal portion of the third fragment, but an atrophic nonunion between the proximal humeral fragment, the distal humeral fragment, and the distal portion of the third fragment developed. The treatment required a technique adapted to this type of nonunion consisting of retrograde flexible intramedullary nailing, cerclage wires, and bone grafts.