2 - Sternal Muscle - Anatomical Review of Literature and Case Report

Poster Board Number: 2
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Abstract Body : Introduction and Objective: The sternal muscle is a rare anatomical variation found
in the anterior chest wall. This study objective was to make a narrative review of the
anatomical and epidemiological aspects of the sternal muscle, as well to present its finding
in one of this group’s dissections.
Materials and Methods: This study consisted in a literature review using Pubmed
and LILACS platforms. Articles were analyzed regarding incidence, laterality, action,
innervation and vascularization of the sternal muscle. We also present a case report based
on a cadaveric dissection of the Hospital das Clínicas, Faculty of Medicine, University of São
Paulo (HCFMUSP).
Results: Our review included 22 articles. The anatomical variation incidence ranged
from 1.96% to 5.55%, with a higher predominance of a bilateral presentation. The action of
the sternal muscle is predominantly accessory and there are divergences in the literature
regarding its innervation and vascularization. Our case reports the finding of a unilateral
sternal muscle in the left paramedian line inserted in both sternocleidomastoid muscles, in a
female patient.
Conclusion: The sternal muscle has a small incidence in the population and it is
usually bilateral. The anatomical knowledge of this muscle is important to prevent it from
being confused with other structures commonly found in the chest and cervical region.
Significance/Implication: The sternal muscle importance cannot be overlooked due
to possible misinterpretations in imaging and its possible influence on mastectomies. Wider
case series are necessary for better definition of its irrigation and innervation.