A rare triple skeletal bone variation, including a median cleft of the posterior arch of the atlas, a sternal foramina and a bifid xiphoid process

Abstract

Bone variations are usually a result of abnormal ossification during embryonic life. Separately or in combination, sternal foramina and bifid xiphoid process are well documented skeletal alternations, as well as the median cleft of the posterior arch of the atlas. However, their appearance in combination is not yet celebrated in the literature. Our post-mortem examination unearthed such a triple variant of an adult male skeleton, which included no other skeletal variations. The fact that all variants are depicted in the median line of ossification implies a hypothesis of a triggered midline bone defect process. The awareness among clinicians of such variations during interventional and imaging procedures is of great importance.

Keywords: Abnormal embryonic ossification; Bifid xiphoid process; Bone variants; Median cleft of the posterior arch of the atlas; Sternal foramina.

Fig. 1. (A) Sternum bone anterior view. 1, manumbrium sternum; 2, body of the sternum; 3, bifid xiphoid process; 4, sternal foramina. (B) Sernum bone posterior view. 1, manumbrium sternum; 2, body of the sternum; 3, bifid xiphoid process (a triangular indicates the bifid shape); 4, sternal foramina (a circle indicates the round shape).

Fig. 2. (A) Stenum bone, lateral view. (B) Atlas bone, dorsal-lateral view.

Fig. 3. (A) Atlas bone superior view. 1, anterior tubercle; 2, duperior articular surface; 3, median open cleft of the posterior arch with no posterior tubercle in present. (B) Atlas bone inferior view. 1, anterior tubercle; 2, Inferior articular surface; 3, median open cleft of the posterior arch with no posterior tubercle in present.