A Hypertrophic Anterior Scalene Muscle and the Passage of a Subclavian Artery Through its Fibres: The Location of Possible Entrapment

Abstract

Objective: The presence of cervical ribs, 1st rib anomalies, cervical muscle hypertrophy and repetitive motion are possible aetiologies of subclavian artery (SCA) entrapment and/or compression. Thoracic outlet syndrome of the arterial type may appear with symptoms of hand pain due to the aneurismal part of the compressed SCA. The current cadaveric case describes a hypertrophic right-sided anterior scalene muscle (ASM) and the possible entrapment of the right SCA (RSCA) passing through its fibres. Furthermore, the branching pattern of the entrapped vessel is analysed.

Case report: A hypertrophic ASM was identified in the right infraclavicular area of a male Greek donated cadaver (70 years of age). The RSCA passed through the ASM belly, and some deeply situated fibres extended posteriorly to the RSCA. The ASM compressed the RSCA against the superior part of the 1st rib.

Conclusion: Knowledge of such variants may be important in the diagnosis of upper limb muscle atrophy or neurosensory loss.

Keywords: Anterior Scalene Muscle; Compression; Subclavian Artery; Thoracic Outlet Syndrome; Variant.