The literature on sacrococcygeal agenesis reviewed in 1959 by Montina and Trabucchi7 lists 63 cases of this anomaly. These authors also report 10 cases of their own. A review of the literature and data on 50 cases, of which 8 were personally observed, was published in 1959 by Blumel, Evans, and Eggers.2 Isolated reports of sacral aplasia continue to appear in the literature.1,3,5,6,8,9 Only cases published after 1959 have been cited, since the literature on this subject has been adequately reviewed.
Investigation and continued interest in the etiology of congenital defects of the spine has yielded 8 additional cases of sacral anomalies which will be the subject of this report. Seven of these patients (2 dead) were seen at John Sealy Hospital, and 1 was furnished by Dr. John A. Knowles, Pleasant Hill, Calif.
Case Reports and Pedigrees
The pedigrees presented diagrammatically in Pedigree Charts I, II,