Anatomical variations of the suprascapular artery: correlation between origin and course.

This study aimed to characterize the spectrum of anatomical variations in the origin and course of the suprascapular artery. We investigated the origin and course of 239 suprascapular arteries from 134 Japanese cadavers donated to Juntendo University School of Medicine for anatomical education. The suprascapular arteries were classified into six types based on their origin and course. Type 1, originating from the thyrocervical trunk, represented the most common and standard morphology (158/239, 66.1%). Type 2 arose from the proximal portion of the internal thoracic artery (15/239, 6.3%), and Type 3 originated directly from the second part of the subclavian artery (10/239, 4.2%). Types 1-3 passed superior to the superior transverse scapular ligament to enter the supraspinous fossa. Type 4 originated directly from the third part of the subclavian artery (50/239, 20.9%), whereas Types 5 and 6 arose from the superior thoracic artery (4/239, 1.7%) and the superficial subscapular artery (2/239, 0.8%), respectively. Types 4-6 traversed the scapular notch inferior to the superior transverse scapular ligament, accompanying the suprascapular nerve, to enter the supraspinous fossa. The brachial plexus sheath, which envelops the brachial plexus and adjacent arteries, was identified as a potential anatomical determinant of the correlation between the origin and course of the suprascapular artery. Type 1 represented the standard morphology of the suprascapular artery. Consistent with previous studies, the suprascapular artery exhibited considerable anatomical variation, with a distinct correlation between origin and course.