Proposal for classification of the suprascapular notch: a study on 423 dried scapulas.

The present study proposes a simple and reproducible method to classify the morphology of the suprascapular notch (SSN), on the basis of specific geometrical parameters that clearly distinguish one type from another. Four hundred twenty-three dried scapulas from the Department of Anatomy in the University of Cologne, Germany, were examined. Five types of SSN were observed: type I, without a discrete notch, 35 (8.3%); type II, a notch that was longest in its transverse diameter, 177 (41.85%); type III, a notch that was longest in its vertical diameter, 177 (41.85%); type IV, a bony foramen, 31 (7.3%); type V, a notch and a bony foramen, 3 (0.7%). For the vertical diameter, we took the maximal diameter of the notch perpendicular to the imaginary line that joins the two superior corners of the notch. For the transverse diameter, we took the diameter perpendicular to the midpoint of the vertical diameter. This classification based on the vertical and the transverse diameters of the SSN suggested a clear distinction of the notch types. This simple classification included all the anatomical variations of the SSN. Using this method, the clinician will be able to define easily and quickly the notch type on a plain radiograph, and perhaps be able to correlate suprascapular nerve entrapment with a specific type of SSN.