RESUMO
PURPOSE: The aim of this study was to determine the anatomical variations of the superior transverse scapular ligament (STSL) for better understanding the possible predisposing factors for suprascapular nerve entrapment. METHODS: The study was using fifty 10% formalin solution-fixed human cadaveric shoulders. After dissection of the suprascapular region, the length, medial width, lateral width and middle width of the suprascapular opening were measured for each STSL. RESULTS: The STSL displayed six types as: (1) band-shaped in 11 cases; (2) fan-shaped in 27 cases; (3) triangular-shaped in 5 cases; (4) linear type in 2 cases; (5) bifid in 1 case; (6) absent in 1 case. The ossified type of STSL was found in 3 cases. There were statistically significant differences in the length (P = 0.009), medial width (P = 0.001), lateral width (P = 0.029) of the three types of fan-shaped, band-shaped and triangular-shaped. However, there was no statistical difference in the middle width of the suprascapular opening of the three types (P = 0.340). CONCLUSION: Knowing the morphological features and variations of the STSL is important for better understanding the anatomical conditions, which could be taken into consideration during open suprascapular operations or arthroscopic decompressions.