Patient Data
Age: 55
Gender: Male
From the case:
Subclavius posticus muscle - an accessory muscle
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There is a curvilinear structure that is isointense to muscle on all sequences (however only T1-weighted images are show here), traveling from the superior angle of the scapula to the sternocleidomastoid (SCM) muscle through the posterior cervical space. This finding is bilateral.
From the case:
Subclavius posticus muscle - an accessory muscle
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The accessory muscle is indicated by the blue asterisks.
Case Discussion
The subclavius posticus muscle is a somewhat rare accessory muscle (although on dissection is found in up to 9% - so maybe not so rare), and may occasionally be associated with thoracic outlet syndrome (TOS); however, there is no evidence of TOS in this case.