Original ArticlesShape of the acromion: Congenital or acquired—A macroscopic, radiographic, and microscopic study of acromion*
Introduction
Irregularity in the shape of coracoid and acromion was first reported by Goldwaite in 1909.1 In 1987 Morrison and Bigliani2 described 3 different types of acromion process (flat, curved, and hooked). They also correlated the rotator cuff tear with the shape of the acromion. Although the data from that study indicate a strong association between cuff tear and hooked acromion, it cannot be determined whether different shapes of acromion process occur as a result of the rotator cuff dysfunctions or rotator cuff tears occur as a result of the curved or hooked shape of the acromion process. So, is the hooking of the acromion a cause of impingement, a result of the impingement, or both? Are the different shapes of the acromion process congenital or acquired?
To determine the answers to these questions, we carried out a cadaveric study of the shoulder joint. Our aim was to investigate the morphology and developmental changes of the acromion by macroscopic, radiographic, and microscopic examination of the acromion process.
Section snippets
Materials and methods
The study included 22 randomly selected cadaveric shoulder joints. Twelve specimens were paired from 6 cadavers, and 10 were unpaired. All of the cadavers were preserved in a standard embalming fluid (a mixture of formalin, phenol, glycerine, spirit, and water). All had died of medical problems such as pulmonary or cardiac conditions. None had upper limb deformity. Their age at death ranged from 69 to 93 years (mean, 81.5 years). There were 8 specimens from female cadavers and 14 from male
Results
Twenty-two cadaveric shoulder joints were studied, but failure in processing left 18 for the final analysis.
Discussion
Our histologic findings have demonstrated that the flat acromions—despite the advanced age of the specimens—show no change in collagen, fibrocartilage, or bone of the anterior and inferior surfaces. However, curved acromions all exhibit marked degenerative changes in the collagen of the coracoacromial ligament and the inferior periosteum. They also showed characteristic hypertrophy in Sharpey's fibers and secondary changes in the underlying bone. In all of these specimens, collagen,
Acknowledgements
We thank Mr J. Stothard (MSc Course Director, University of Teesside), Mr S. C. Deshmukh (Consultant Orthopaedic Surgeon), Carol Cresswell (Histopathology Department, RVI), Dr A. Coulthard (Consultant Radiologist, RVI, Newcastle upon Tyne), Mrs C. E. Harkness, and Dr D. Shanahan (Anatomy Department, University of Newcastle upon Tyne), and Dr G. Weston for their help in this project.
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Acute, Traumatic Rotator Cuff Tears Have Smaller Critical Shoulder Angles Than Degenerative Tears
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2019, Arthroscopy - Journal of Arthroscopic and Related SurgeryCitation Excerpt :The meta-analysis showed that hook-shaped acromion (type III) was indicative of a higher risk for rotator cuff tears. Previous studies have indicated that, rather than having a congenital origin, a type III acromion may be acquired progressively due to mechanical traction that, in turn, can lead to degenerative bone changes.80-82 Furthermore, acromion shape is more related to its anterior slope, which has no direct relationship with the rotator cuff.
Critical shoulder angle: Measurement reproducibility and correlation with rotator cuff tendon tears
2016, Orthopaedics and Traumatology: Surgery and ResearchCitation Excerpt :Types II and III were more common in the RCT group. The impact and aetiology of acromion geometry according to Bigliani remain controversial [12,15,24–29]. We are not aware of published evidence that the lateral acromion changes with age.
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2016, Rockwood and Matsen’s The Shoulder
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Reprint requests: Nirav N. Shah, MBBS, MS(Orth), MSc(Orth), 42, Sandhurst Rd, Tunbridge Wells, Kent, TN2 3JT, United Kingdom.