CASE 12312 Published on 04.02.2015
0

Sternal foramen

Section

Chest imaging

Case Type

Anatomy and Functional Imaging

Authors

Luís Amaral Ferreira, Marta Sofia Barros, João Filipe Costa, Filipe Caseiro Alves

Serviço de Imagem Médica
Centro Hospitalar e Universitário de Coimbra
Praceta Prof. Mota Pinto
3000-075 COIMBRA
PORTUGAL
Corresponding author: luisamaralferreira@gmail.com
Connected authors
Patient

78 years, male

Categories
Area of Interest Bones, Musculoskeletal bone ; Imaging Technique CT
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Clinical History
A 78-year-old man with clinical history of pulmonary nodules came for a follow-up chest CT examination.
Imaging Findings
Analysis of the axial images with coronal and sagittal reformation (Fig. 1 a-c) shows a defect on the body of the sternum at the level of the insertion of the 4th and 5th costal arches. This bone defect has 22 mm on the largest axis and is filled with fat density tissue (Fig. 1 d) that is contiguous with epicardial fat. The defect is surrounded by well-corticalized sternum.
Figure 2 shows a volume rendering of the sternum where the bone defect is evident.
Apart from pulmonary nodules no other significant alteration was noticed.
Discussion
The normal sternum is a bone composed by three segments: the manubrium, body and xyphoid process. Sternum development starts with the fuse at midline of two mesodermic plates that give rise to six centres of ossification. The ossification and fusing of bone segments starts at the most cranial centre, the manubrium, and progress caudally [1].
A defect of ossification or fusing on the lower third of the body of the sternum can lead to a so called sternal foramen [1, 2]. This anatomical variation has a prevalence of around 6% in some autopsy and CT series [3, 4]. Association of this defect to displacement of the heart, midline abnormalities and accessory fissures on the left lung have been reported [5].
This defect might be confused with a bullet hole or even with a bone lesion [4, 6].
Complications of otherwise safe procedures such as acupuncture or bone marrow aspiration have been reported in individuals with this variant [6]. One example in the literature is a fatal heart tamponade after the insertion of an acupuncture needle over the lower third of the body of the sternum which, due to the presence of a strenal foramen, pierced the right ventricle [7].
Acknowledging the existence of sternal foramen is of key importance to the radiologist so as not to mistake this anatomical variant for a bone lesion. It is also fundamental to the clinician to be aware of its existence and to search for it before performing bone marrow aspiration on the lower portion of the body or even acupuncture.
Differential Diagnosis List
Sternal foramen
Normal variant
Lytic lesion
Final Diagnosis
Sternal foramen
Case information
URL: https://www.eurorad.org/case/12312
DOI: 10.1594/EURORAD/CASE.12312
ISSN: 1563-4086
Figure 1

Chest CT examination

Chest CT examination
Axial
Chest CT examination
Coronal
Chest CT examination
Sagittal
Chest CT examination
Axial in soft tissue window
Figure 2

Volume rendering of the sternum

Volume rendering of the sternum
3D rendering of the sternum showing the defect.