Normal Glenohumeral Geometry by Computed Tomography

The stability of the glenohumeral joint depends basically on the periarticular soft tissue – capsule, ligaments, tendons, and muscles; but the bony geometry was also taken into account by some authors. The normal version described on textbooks are glenoid tilting about 4-8∘backwards and humeral head with 25-40∘retroversion. These guidelines are also important in shoulder arthroplasty. But those data all came from the western world. So, we may ask what are the normal values in Chinese? To answer this question, the authors use the CT scan (GE 9800) to measure the glenohumeral geometry of 48 shoulders in 24 patients. There are 13 male and 11 female, and the age ranged from 35 to 83 years, mostly in the sixth decade. The CT films were digitized with back-slit digitizer and ResearchMetrics software. The results are : the mean glenoid width is 2.65 ± 0.31 cm; the mean diameter of humeral head is 4.27 ± 0.39 cm; the average glenohumeral index is 62%; the glenoid changes from retroversion proximally to anteversion distally with an overall 5.3∘retroversion; and the overall humeral retroversion is 18.2∘, much smaller than those previous reports. The differences between Chinese and Caucasian are: relatively wider glenoid and less retroversion of the humeral head. There was no correlation between ROM and the glenoid or humeral version. These findings should raise interest in clinical implication.

並列關鍵字

glenohumeral geometry ； shoulder anatomy ； glenoid retroversion ； humeral retroversion ； shoulder instability

國際替代計量

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