Subclavius posticus muscle - an accessory muscle

Case contributed by Dr Matt Skalski

Patient Data

Age: 55
Gender: Male

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. 

Annotated image

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. 

PlayAdd to Share

Case information

rID: 30797
Case created: 4th Sep 2014
Last edited: 27th Apr 2017
Inclusion in quiz mode: Included

Updating… Please wait.
Loadinganimation

Alert accept

Error Unable to process the form. Check for errors and try again.

Alert accept Thank you for updating your details.