Pelvic Digit


Author Affiliation
Jennifer Carnell, MD Alameda County Medical Center, Highland General Hospital, Department of Emergency Medicine
Christopher Fee, MD University of California, San Francisco Medical Center, Division of Emergency Medicine, Department of Medicine

A 48-year-old female with systemic lupus erythematosus and renal failure was admitted to the hospital with pyelonephritis. While in the emergency department (ED), during transfer to a bedside commode, she slipped to the floor and subsequently reported right lateral hip pain. Examination revealed mild tenderness to palpation in that area. Radiographs were obtained and demonstrated a pelvic digit (indicated by arrow). What may be mistakenly interpreted radiographically as a fracture of the pelvic digit is actually a pseudoarticulation, a common finding near the base of the pelvic digit. Also referred to as a pelvic rib or an iliac rib, a pelvic digit is a rare, congenital anomaly that is usually asymptomatic and, therefore, found incidentally by plain radiograph. Pelvic digits are most often associated with the ilium but may also pseudoarticulate with other pelvic bones or the abdominal wall.1 Their well-corticated appearance without defect facilitates differentiation from post-traumatic myositis ossificans, heterotopic bone formation, ligamentous calcifications and fracture. 2 As in the case of our patient, radiographs are often obtained in the ED in the setting of trauma. Consequently, it is important to consider the benign entity of pelvic digit as a possibility and avoid further unnecessary work-up.



Supervising Section Editor: Rick A. McPheeters, DO
Submission history: Submitted February 23, 2008; Revision Received Aril 1, 2008; Accepted April 3, 2008.
Full text available through open access at

Address for Correspondence: Jennifer Carnell, MD, Department of Emergency Medicine, Alameda County Medical Center, Highland Hospital, 1411 East 31st Street, Oakland, CA 94602

Conflicts of Interest: By the WestJEM article submission agreement, all authors are required to disclose all affiliations, funding sources, and financial or management relationships that could be perceived as potential sources of bias. The authors disclosed none.


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2. Nguyen VD, Matthes JD, Wunderlich CC. The pelvic digit: CT correlation and review of the literature. Computerized Medical Imaging and Graphics. 1990;14:127–31. [PubMed]