Anatomical features of suprascapular notch: correlation with scapular dimension and clinical relevance.

Introduction An improved knowledge of the suprascapular notch anatomy may help to prevent and to well-assess the suprascapular nerve entrapment syndrome. We aimed to verify the reliability of the existing data, to assess the differences between the two genders, to verify the existing correlation between the dimensions of the scapula and of the suprascapular notch, to investigate the relationship between the suprascapular notch and the postero-superior limit of the safe zone for the suprascapular nerve. Materials and methods We examined 500 dried scapulae, measuring seven distances referring to the scapular body and suprascapular notch; they were also catalogued according to gender, age and side. Suprascapular notch was classified according to Rengachary’s method. We elaborated for each class the width/depth ratio. Pearson’s correlation was also calculated. Results Frequencies were: Type I 12.4 %, Type II 19.8 %, Type III 22.8 %, Type IV 31.1 %, Type V 10.2 %, Type VI 3.6 %. Width and depth showed a not statistical significant difference when elaborated according to gender and side; a significant difference was found between the depth means elaborated according to median age (73 years old). Correlation indexes were weak or not statistically significant. The difference between the postero-superior limit of the safe zone in the six types of notches was not statistical significant. Discussion We observed a difference concerning the frequencies of the VI Types of suprascapular notch presented in our study respect to those reported in literature. We suppose that the difference between the depth means may be due to the most frequent presence of partial/total ossification of the superior transverse scapular ligament in the population over 73 years old. The characteristics of the suprascapular notch (dimensions and type) are not influenced by age, gender and scapular dimensions. Conclusions A pre-operative evaluation of the patient’s characteristics (gender, age and scapular dimensions) does not provide any information about the suprascapular notch. The safe zone is not influenced by the morphologic and morphometric characteristics of the suprascapular notch.