A sesamoid ossicle of the nuchal ligament mimicking spinous avulsion fracture

Abstract

A 25-year-old man who suffered a traffic accident was admitted to our emergency department. Computer tomography was performed. Computer tomography images showed an osseous structure mimicking avulsion fracture at the level of C5–C6 (Fig. 1). There was no bone defect corresponding to spinous process and so, the diagnosis was consistent with sesamoid ossicles of the nuchal ligament. Sesamoid ossicles of the nuchal ligament are an anatomical variant that are usually asymptomatic. Prominent differential diagnosis includes avulsion fractures of the spinal processes and myositis ossificans. Focal well-defined osseous masses, well-circumscribed with regular shape, are in favor of sesamoid ossicle of nuchal ligament, whereas triangular dense bony fragment with bony defect of the adjacent spinous process are in favor of spinous process fracture. Ihsan Yuce, MD Berhan Pirimoglu, MD Gokhan Polat, MD Recep Sade, MD Mucahit Emet, MD Mecit Kantarci, MD, PhD Department of Radiology, School of Medicine Ataturk University 25100 Erzurum, Turkey Department of Emergency Medicine, School of Medicine Ataturk University 25100 Erzurum, Turkey