A Comprehensive Review of the Sternal Foramina and its Clinical Significance

Discovery of an Anteriorly Deviated, Partially Ossified Xiphoid Process With a Large, Teardrop-Shaped Foramen in a Male Cadaver

The sternum, or "breastbone," is a principal bony component of the anterior thoracic wall and comprises the manubrium of the sternum, the body of the sternum, and the xiphoid process. The xiphoid process is the most inferior of these elements and commonly presents as a small, solid bone shaped like an inverted triangle. However, clinical literature has reported numerous variations in its size, shape, and presentation, likely the result of its lengthy embryological development from cartilage into fully ossified bone. In this case report, a rare, anteriorly deviated, partially ossified xiphoid process with a large, teardrop-shaped foramen is presented that was discovered during a routine cadaveric dissection of a 75-year-old male within an undergraduate anatomy course. Although anatomical variations in the xiphoid process are often asymptomatic and often only found incidentally through CT or X-ray scans, healthcare professionals should be aware of such variations to avoid both misdiagnoses as well as iatrogenic complications.

Anatomical variations of the sternum: sternal foramen and variant xiphoid morphology in dried adult human sternum in Ethiopia

Background: The sternum exhibits unique anatomical variations with major clinical and forensic implications. This study is devoted to providing baseline epidemiological information about the sternal foramen and variant xiphoid morphology in Ethiopia. Two extremely interesting and unusual variations of the sternal foramen are also discussed. Methods: This observational study was carried out using dried adult human sternum obtained from skeletal remains samples brought for medicolegal examination over a period of 4 years. A total of 94 dried adult human sternums (66 males (70.2%) and 28 females (29.8%)) were obtained with an age range of 21 to 57 years and a mean age at death of 38.383 ± 11.3480 years. Dried human sternum specimens were morphologically examined, and morphometric parameters were recorded and photographed. Results: A sternal foramen was found in 18 specimens (19.1%); 17 were male and one was female. A single sternal foramen was observed in 83.3% (n=15/18) of the sternal bodies and 11.1% (n=2/18) of the xiphoid processes (both males). In addition, a double sternal foramen was observed in a single male specimen on the mesosternum and xiphoid process. The most common sternal foramen site was at the fifth costochondral junction level. The xiphoid process was present in 77 samples and ended as a single process in 83.1% (n=64/77) of samples. In 15.6% (n=12/77) of the samples, the xiphoid process was bifurcated and trifurcated in a single male (1.3%) specimen. Conclusions: The sternal foramen and variation in xiphoid morphology are common anatomical variations in Ethiopia. The findings of the current study highlight the necessity of strict precautionary measures during sternal procedures in this study population. In addition, such incidental findings during radiologic and autopsy procedures should be properly evaluated to avoid misdiagnosis and misinterpretation of such findings as traumatic or pathologic conditions.

Prevalence and morphometry of sternal and xiphoid foramen: a meta-analysis on 16,666 subjects

PURPOSE

Sternal foramen is a perforation of the sternum that can be a source of misdiagnosis during radiographic imaging or life-threatening perforations during bone marrow sampling. The aim of this study was to conduct a meta-analysis on the prevalence, morphometrics, and location of foramen in the sternal body and xiphoid process, describe morphometric features of this phenomenon, and thus verify its clinical importance. Moreover, our secondary outcome was to compare effectiveness of various imaging methods in diagnosis of the sternal or xiphoid foramen.

METHODS

A comprehensive search was conducted on major scientific databases to identify studies containing relevant information. Data on foramen's prevalence, location, morphometrics, and accompanying findings were extracted and pooled into a meta-analysis using MetaXL 5.0.

RESULTS

Thirty-five studies (n = 16,666 subjects) were included. The overall pooled prevalence of a foramen in the sternal body and/or a xiphoid process was 8.9% (95% CI 6.5-11.7) and it equaled 6.5% (95% CI 5.6-7.6) for sternal body alone and 2.9% (95% CI 0.5-6.9) for the xiphoid process. The foramen was more prevalent in males than in females (12.2% vs. 6.8%). The prevalence of sternal foramen was higher in South American [13.9% (95% CI 11.2-16.9)] and African [13.6% (95% CI 9.7-18.0)] studies compared to North American [6.2% (95% CI 5.0-7.5)] and European populations [8.6% (95% CI 3.1-16.3)]. Mean transverse and vertical diameter of foramen equaled 4.7 mm (95% CI 3.8-5.5), and 5.6 mm (95% CI 4.2-6.9), respectively.

CONCLUSION

Our analysis proves that the sternal foramina are structures of significant prevalence and size. Any physician should keep them in mind when performing punctures in this area.

High prevalence of sternal foramina in indigenous Bolivians compared to Midwest Americans and indigenous North Americans (sternal foramina in indigenous Bolivians)

The sternal foramen, usually an asymptomatic osteological defect, can lead to catastrophic consequences if not recognized prior to certain medical procedures. This study reports the prevalence of a sternal foramen in two South Amerindian populations compared with other published populations. We evaluated the presence of sternal foramina using thoracic computed tomography scans of 1334 (48% female) participants from two indigenous populations of Bolivia (n = 900 Tsimane, 434 Moseten). The prevalence of sternal foramina was compared to two U.S. populations of similar sex/age distribution (n = 572 Midwest Americans, 131 self-identified Native North Americans) via similar CT scans. A sternal foramen was significantly more common in the two Bolivian populations (prevalence ranging from 12.8 to 13.4%), compared to 4.4-5.1% in the two U.S. groups, consistent with prior estimates in studies from industrialized populations. Males had higher frequency of a sternal foramen compared to females in each of the four groups (OR = 1.904, 95% CI: 1.418-2.568, p < 0.001). Age was not associated with sternal foramen presence. These data show both a higher rate of sternal foramina in the South Amerindian populations versus comparator populations in North America and the highest rate of any studied living population. Although it is not possible to determine from our data the relative contribution of genetics versus early life or environmental causes to the higher rates of sternal foramen, we note that small prior studies have likewise demonstrated a higher prevalence in lower income countries. Further determination of the contributing factors warrants greater investigation and research.

Ultrasound and bone: a pictorial review

The assessment of bone mainly relies on standard radiographs, CT, MRI, and bone scintigraphy depending on the anatomic region complexity and clinical scenario. Ultrasound (US), due to different acoustic impedance between soft tissues and the bone cortex, only allows the evaluation of the bone surfaces. Nevertheless, US can be useful in the evaluation of several bone disorders affecting the limbs as a result of its tomographic capabilities and high definition. This pictorial review article summarises our clinical experience in adults and reviews the literature on US bone examination. We first present the US appearance of normal bone and the main congenital anatomic variations, after which we illustrate the US findings of a variety of bone disorders. Although US has limits in bone assessment, its analysis must be a part of every musculoskeletal US examination.

Topographic evaluation of sternal foramen patients with thoracic computed tomography

PURPOSE

In our study, we aimed to determine the topographic analysis of sternal foramen cases incidentally detected in patients underwent thoracic computed tomography.

MATERIALS AND METHODS

Patients aged 18 and over who were admitted to the thoracic surgery outpatient clinic for various reasons and underwent thoracic computed tomography (CT) between January 1, 2018 and January 1, 2019 were evaluated retrospectively. Thoracic CT scans of all patients with sternal foramen were evaluated by applying 3D bone configuration to evaluate foramina in the sternum and ribs. The data obtained were analyzed statistically by SPSS (Statistical Package for Social Sciences Version 21.0).

RESULTS

Nine hundred and twelve patients were evaluated and sternal foramen prevalence was found to be 8.44% in our study. Of the 68 patients included in the study, 48 were male and 20 were female. The sternal foramen was localized in the corpus in 66.2% of the patients, whereas it was localized in xiphoid in 33.8%. Nine patients had scoliosis deformity and three patients had foramen in the rib.

CONCLUSION

Sternal foramen is a more common defect than thought, and should be kept in mind in clinical practice to prevent complications.

Honeycomb sterna: an unusual case of a developmental abnormality in the sternum

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.

Bifid Xiphoid Process: Case Report and Review

The xiphoid process is a bony process that comprises part of the sternum. This anatomical structure exhibits several morphological variations, which may complicate diagnostic examinations and invasive thoracic procedures. Variations include bifurcated or trifurcated, deflected, and curved processes. This report discusses a case of a bifid xiphoid process during cadaveric dissection and compares similar findings in the literature. The aim is to improve our knowledge of anatomical variations in an effort to reduce complications and improve patient care.