Suprascapular nerf block - best location for infiltration in chronic shoulder pain

Fossa suprascapularis long resp.  (left is medial)

What is the name of the anatomic structure (bold arrows)? -  which is also the best location for us guided infiltration of the suprascapular nerf (SSN)?
Should the suprascapular artery be located below or above the transverse ligament?
http://www.ncbi.nlm.nih.gov/pubmed/20052627