Abstract
Purpose
To report a previously undocumented variant of sternalis.
Methods
An unusual muscle was observed during routine dissection.
Results
The sternalis muscle located in the right thoracic region originated from the superior portion of the rectus abdominis sheath and 5–6th costal cartilages, crossed the midline and attached at the sternum. The muscle fibers then ascended with the left sternocleidomastoid muscle as an additional fasciculus, of which the superior ends were finally terminated at the left mastoid process. The sternalis muscle of the thoracic region was innervated by the anterior cutaneous branches of right intercostal nerve, while the additional fasciculus ascended with the left sternocleidomastoid muscle was innervated by the branches of left accessory nerve.
Conclusions
This study presents a unilateral sternalis muscle with the contralateral sternocleidomastoid variation. It will enhance the exhaustive classification of sternalis, and provide significant information to radiologists, angiologists and surgeons for better interpretation of images and safer interventions.
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Acknowledgements
The authors show great appreciation to the body donor.
Funding
This study was funded by Guangdong Teaching Reform Projects of Higher Education (2020-20) and Honor Program for Basic Medicine of Sun Yat-Sen University.
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Contributions
XW, HZ, JC, HZ, YF, YW, ZC, RZ, and LZ: dissection, data collection, data analysis, and manuscript writing. KG, DX, and JD: data collection and manuscript writing.
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The authors declare that they have no conflict of interest.
Ethical approval
The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Zhongshan School of Medicine, Sun Yat-Sen University.
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Wang, X., Zou, H., Chen, J. et al. An unusual sternalis with variation of the contralateral sternocleidomastoid muscle: a case report. Surg Radiol Anat 44, 987–990 (2022). https://doi.org/10.1007/s00276-022-02980-1
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DOI: https://doi.org/10.1007/s00276-022-02980-1