Scapular morphological variations and sex-related and generational differences in global scapular shape:...

The objectives of the present study were to perform a three-dimensional morphometric analysis of global scapular shape in 500 individuals using homologous modeling and to examine sex-related and generational differences in global scapular shape.

Computed tomography images of the scapulae of 500 individuals were obtained. A homologous model of the scapula, comprising 19,563 vertices, was created based on 40 landmarks. Principal component analysis of the three-dimensional coordinates of all vertices was performed. The morphological variation represented by each principal component (PC) was interpreted based on the virtual shape of each loading score, a 2-way analysis of variance of PC scores was conducted to assess sex-related and generational differences.

Men had the following characteristics compared with women, the scapular body was longitudinally longer than transversely (PC1); the lateral morphology was posteriorly inclined, and the scapular body was anteriorly inclined (PC2); the acromion was anteriorly oriented, and anteroposterior diameters of the scapular body and supraspinous fossa were increased (PC5); the acromion and coracoid process were anteriorly oriented, and the width of the scapular body was increased medially and laterally (PC6). The older age group showed a tendency toward having a posterior tilt of the lateral morphology and an anterior tilt of the scapular body (PC2), a medial orientation of the acromion, and increased anteroposterior diameter of the supraspinatus fossa (PC3) compared with the younger age group.

We observed several variations in the global shape of the scapula. Sex-related and generational differences in global scapular shape were clarified. These differences may be considered when analyzing scapular morphology.