Morphological study of the attachment of sternocleidomastoid muscle.

Introduction: The sternocleidomastoid (SCM) muscle is a major muscle of the neck. Classically, this muscle is attached below the sternum and clavicle, although the mode of attachment might vary. As the SCM is related to numerous important neurovascular structures, its variable anatomy is clinically relevant, particularly for neck surgeries. A cadaveric study was performed to establish the variations present in the mode of attachment of the SCM muscle in an Indian population.
Methods: We studied the variations in the attachment of the SCM muscle during the dissection of 18 cadavers for undergraduate teaching in two medical colleges in West Bengal, India.
Results: Variations in the attachment of the SCM muscle were found in 5 (27.8%) specimens. Of these five specimens, three had unilateral variations and two had bilateral variations. In each specimen, the modes of presentation of the SCM and its fusion with the major bulk were also different.
Conclusion: In this study, we found variations in the attachment of the SCM muscle in more than a quarter of the specimens dissected. Surgeons should bear in mind such variations when performing neck surgeries.