“Iliac Horns” (Symmetrical Bilateral Central Posterior Iliac Processes)

A case of “iliac horns” (symmetrical bilateral central posterior iliac processes) is reported here because of the extremely unusual nature of the condition.

The patient presenting this anomaly was a 27-year-old woman with a mild hypertension developing during her first pregnancy. She failed to respond to pre-eclampsia treatment, and labor was induced on Sept. 17, 1944 A low forceps delivery was made after full dilatation of the cervix and an episiotomy. On Oct. 31, 1944, the vascular tension remained slightly elevated, but the urine had become free of albumin. The patient first came under the observation of the writer in January 1945, at which time intravenous pyelography was performed. Nothing unusual was demonstrated in the upper urinary tract, but bilateral smooth-surfaced bony protrusions were observed on the central portions of the ilia, and the patient was asked to return for further examination. On this subsequent examination (Figs. 1 and 2), the bilateral symmetrical iliac processes were found to arise from the posterior surfaces of the ilia. The processes measured approximately 2.5 cm. in diameter and projected laterally as well as posteriorly a distance of about 3 cm. The pelvic inlet was somewhat anthropoid in shape posteriorly. The inferior halves of the sacro-iliac joints were considerably more oblique than usual, so that a projection of lines drawn tangential to their surfaces would intersect at approximately a 90-degree angle at the sacrococcygeal junction. The plane of the lumbosacral articulation was more horizontal than usual. Although the patient had never realized the presence of the “iliac horns,” these were easily palpable.

We were unable to recall ever having observed such “iliac horns” or reading any account of them. Since a search of the medical literature available to us failed to add any information, a copy of one of the films was sent to Dr. L. H. Garland for his opinion and assistance. He, too, had never seen such an anomaly and suggested a search of texts on comparative anatomy and enlistment of the help of the Director of the Army Medical Museum. The latter in turn referred the matter to Colonel A. A. de Lorimer, Commandant of the Army School of Roentgenology. A portion of his reply is quoted:

“An effort was made to find reference in the literature to this type of anomaly, but to no avail.

“We presented these films at one of our Monday evening sessions, where there were in attendance some thirty or forty doctors, including a dozen or more well qualified orthopedic surgeons (Drs. Speed, Boyd, Major Flanagan, Captain Haddon, and others from Kennedy General Hospital). No one has seen anything like your case.”