Morphometric study of the suprascapular notch: proposal of classification

Abstract

The size and shape of the suprascapular notch (SSN) may be a factor in suprascapular nerve entrapment. The aim of the study was to determine the variation of the SSN of 86 scapulae in the Polish people. A total of 86 human scapulae were included in the study. Three measurements were defined and collected for every SSN: maximal depth (MD), superior (STD) and middle (MTD) transverse diameters. The measurements of the SSN were taken using two complementary methods: classical osteometry and a new one based on the analysis of digital photographic documentation of the SSN taken using MultiScanBase v.14.02 software. The analysis allowed determining five types of SSN. Type I has a longer maximal depth than superior transverse diameter (24.4%). Type II has equal MD, STD and MTD (2.3%). Type III has a superior transverse diameter longer than the maximal depth (54.7%). Type IV was a bony foramen (7%). Type V has a discrete notch (11.6%). Types I and III were divided into three subtypes: A (MTD was longer than STD), B (equal, MTD = STD) and C (inversely, MTD < STD). Superior transverse suprascapular ligament was completely and partially ossified in 7 and 23.3%, respectively. The presented quantitative classification of the SSN is simple and based on specific geometrical parameters that clearly distinguish five structural types and could be used in the further investigation in computer tomography or ultrasonography. The ossification of the superior transverse scapular ligament (STSL) in the study of the Polish people was similar to that described in Germany, France and Italy.