A quantitative study of the arrangement of the suprascapular nerve and vessels in the suprascapular notch region: new findings based on parametric analysis

Abstract

Background: When closed by the superior transverse scapular ligament (STSL), the suprascapular notch (SSN) creates an osseo-fibrous tunnel which acts as a pathway for the suprascapular nerve (SN). Anatomical variations are common in this region, and these can increase the risk of neuropathy by restricting the space for nerve passage. The aim of this study is to identify any correlation between the area reduction coefficient parameters and the SN and vessel arrangements in the SSN region.

Material and methods: The SSN region was dissected in 88 formalin-fixed cadaveric shoulders (40 left and 48 right). During dissection, the topography of the SN, artery and vein was evaluated. Quantitative visual data analysis software was used to measure the areas of the STSL and the anterior coracoscapular ligament (ACSL), as well as the diameters of the SN and associated vessels, and to assign those structures to existing classifications. The area reduction coefficient (ARC) was calculated for each shoulder.

Results: The area of the STSL (aSTSL) and ACSL (aACSL) were significantly larger in Type IV than Type I of the triad. Similarly, the aSTSL and area of the SSN (aSSN) were found to be significantly larger in Type IV than Type III. However, no significant differences were found in the ARC of the STSL (ARC_STSL), the ARC of the ACSL (ARC_ACSL) or the total ARC (ARC_total).

Conclusions: Although the aSTSL, aACSL and aSSN varied according to the type of SN and vessel arrangement, coefficient analysis (ARC_STSL, ARC_ACSL and ARC_total) indicated that combined effect of these variations did not significantly affect SSN morphology.