This report details an unusual case of a human sternal developmental abnormality of an anatomical specimen part of the skeletal collection curated by University College London, Anthropology Department skeletal collection. This rarely reported developmental abnormality is caused by the non-fusion of lateral ossification centres in the sternebrae, resulting in the mesosternum having a honeycomb-like appearance. Sternal defects are typically underreported in the clinical literature as many cases being asymptomatic that they are typically diagnosed incidentally, as such there is a dearth in our current understanding of the development and anatomical variants of the sternum. Although in recent years, large-scale CT studies have investigated the prevalence of sternal developmental abnormalities, these studies have not reported sternal defects similar to the individual presented in this report. While most sternal defects are clinically uneventful, the lack of awareness of these variants can result in misinterpretation of radiological and pathological findings as such an understanding of anatomical variants even when asymptomatic is vital.