Anatomical variations of the sternal angle and anomalies of adult human sterna from the Galloway osteological collection at Makerere University Anatomy Department

BACKGROUND: Anatomical variations of the sternal angle and anomalies of the sternum are unique happenings of major clinical significance. It is known that misplaced sternal angles may lead to inaccurate counting of ribs and create challenges with intercostal nerve blocks and needle thoracostomies. Sternal foramina may pose a great hazard during sternal puncture, due to inadvertent cardiac or great vessel injury. These sternal variations and anomalies are rarely reported among Africans. The aim of this study was to determine the anatomical variations of the sternal angle and anomalies of the sternum among adult dry human sterna at the Galloway osteological collection, Makerere University, Uganda. MATERIALS AND METHODS: This was a descriptive cross sectional study in which quantitative and qualitative data were collected. The study examined 85 adult human sterna at the Department of Anatomy, Makerere University. Univariate and bivariate analyses were done using SPSS 21.0 for Windows. RESULTS: Over 40% (36/85) of the specimens had variations in size, location and fusion of the sternal angle. There was no significant difference in the mean size of the sternal angle in males at 163.4 ± 6.7o compared with 165.0 ± 6.4o in females (p = 0.481). Of the 85 specimens examined, only 21 (24.7%) had a xiphoid process. The most frequent sternal anomalies were bifid xiphoid process 42.9% (9/21) and sternal foramen 12.9% (11/85). CONCLUSIONS: Sternal variations and anomalies are prevalent in the Galloway osteological collection and there is need for increased awareness of these findings as they may determine the accuracy of clinical and other procedures in the thoracic region.