Abstract
Purpose
Anatomical variations of the sternocleidomastoid muscle (SCM) have been observed to occupy multiple origins and insertion points and have supernumerary heads, sometimes varying in thickness.
Methods
An 85-year-old Korean male cadaver was dissected and a SMC with unilateral supernumerary heads was identified.
Results
Three heads and an accessory belly of the sternal head were recorded on the left side. There were two clavicular heads, one lateral and one medial. The sternal head originated inferior to the manubrium of the sternum. A small belly arose from the sternal head and merged to the lateral clavicular head on the C5 vertebrae level. These bellies inserted into the mastoid process of the temporal bone.
Conclusions
These variants may be problematic during surgical approaches to the upper neck and occipital, and should thus be appreciated by the clinician.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Brennan PA, Alam P, Ammar M, Tsiroyannis C, Zagkou E, Standring S (2017) Sternocleidomastoid innervation from an aberrant nerve arising from the hypoglossal nerve: a prospective study of 160 neck dissections. Surg Radiol Anat 39:205–209
Dupont G, Iwanaga J, Altafulla JJ, Lachkar S, Oskouian RJ, Tubbs RS (2018) Bilateral sternocleidomastoid variant with six distinct insertions along the superior nuchal line. Anat Cell Biol 51(4):305–308
Hasan T (2010) Variations of the sternocleidomastoid muscle: a literature review. Int J Hum Anat 2(1):1–6
Hurtado DKA, Arquez HF (2016) Bilateral supernumerary sternocleidomastoid heads with clinical and surgical implications. J Chem Pharm Res 8(5):527–537
Kennedy E, Albert M, Nicholson H (2017) The fascicular anatomy and peak force capabilities of the sternocleidomastoid muscle. Surg Radiol Anat 39(6):629–645
Kim SY, Jang HB, Kim J, Yoon SP (2015) Bilateral four heads of the sternocleidomastoid muscle. Surg Radiol Anat 37(7):871–873
Kohan EJ, Wirth GA (2014) Anatomy of the neck. Clin Plast Surg 41(1):1–6
Mehta V, Arora J, Kumar A et al (2012) Bipartite clavicular attachment of the sternocleidomastoid muscle: a case report. Anat Cell Biol 45(1):66–69
Oh J, Kim C, Kim J, Yoon S (2019) Bilateral supernumerary clavicular heads of sternocleidomastoid muscle in a Korean female cadaver. Surg Radiol Anat 41(6):699–702
Rao TR, Vishnumaya G, Prakashchandra S, Suresh R, Ramesh R, Vishnumaya G (2007) Variation in the origin of sternocleidomastoid muscle. Int J Morphol 25(3):621–623
Tubbs RS, Shoja MM, Loukas M (2016) Bergman’s comprehensive encyclopedia of human anatomic variation. Wiley, Hoboken
Acknowledgements
This study was supported by Grants from the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Korean Government (MSIP) (no. 2014R1A5A2010008).
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that they have no conflicts of interest with the contents of this article.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Heo, YR., Kim, JW. & Lee, JH. Variation of the sternocleidomastoid muscle: a case report of three heads and an accessory head. Surg Radiol Anat 42, 711–713 (2020). https://doi.org/10.1007/s00276-019-02388-4
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00276-019-02388-4