Examining changes in acromial morphology in relation to spurs at the anterior edge of acromion

Background: Although acromial morphology is classified as flat, curved, and hooked, whether the morphology is primary or acquired is debated. There have been no investigations on the effect of acromial spurs on acromial morphology. This study therefore aimed to evaluate acromial morphology in relation to spur formation at the anterior edge of the acromion.

Materials and Methods: Acromial morphology was investigated in 40 scapulae taken from 20 cadavers (10 male and 10 female), with a median age of 82 years (range 62-97 years). Ink prints of the anteroposterior aspect of the acromion were used to evaluate acromial slope angle and curvature height in relation to spur incidence, length, and shape at the anterior edge of the acromion.

Results: Differences were observed in acromial morphology and acromial curvature in relation to acromial spurs (incidence, size, and shape). A hooked acromion was observed as a primary structure in 25% of specimens, which increased to 43% when acromial spurs were involved. No differences were observed in relation to sex or side, while a significant correlation was observed between acromial curvature and the age of the specimens.

Conclusion: Acromial spurs increase acromial curvature and therefore change acromion morphology. Nevertheless, it is concluded that a hooked acromion occurs as a primary formed structure.

Level of Evidence: Basic science study, anatomy, cadaver dissection.