1. In the case presented, the operative findings definitely show that the anomaly itself was the cause of the patient's low-back pain.
2. Microscopic and gross studies of this anomalous bone show that it is not a fracture nor the result of 'Umbauzonen', but that it is a definite developmental abnormality, epiphyseal in character.
3. Embryological study reveals the probability that these anomalies represent a failure of fusion of one of the normally present primary ossification centers lying at the base of the articular facet, and they probably are not anomalous ununited epiphyses or accessory bones.
(C) 1939 All Rights Reserved.The Journal of Bone and Joint Surgery, Inc.