Magnetic Resonance Imaging of the Subcoracoid Region and Its Relationship with Subscapularis Lesions in the Chinese Population

Introduction: Coracoid impingement is considered a known yet frequently overlooked cause of anterior shoulder pain. Subcoracoid stenosis has been shown to be related to subscapularis tear. Studies have shown that patients with coracoid impingement have a shorter coracohumeral distance (CHD) and a larger coracoid overlap (CO) but these are based on data from Western populations. The aim of our study was to provide a local database on the MRI measurement of these parameters in our Chinese population and raise the awareness of this disease entity. Methods: All the shoulder MRI films taken in our hospital in 2011 were retrospectively reviewed and classified into two cohorts. The control group consisted of patients who had no subscapularis lesion. The subscapularis lesion group consisted of patients with complete tear, partial tear or abnormal signal over the subscapularis tendon. The CHD and CO were measured. Results: We reviewed 133 sets of shoulder MRI obtained in our hospital during 2011. Thirteen patients were noted to have subscapularis lesion. The CHD in the subscapularis lesion group was 6.24 +/- 2.18 mm. The CHD in the control group was 9.95 +/- 3.9 mm. Women had shorter CHD (8.18 +/- 2.57 mm) than men (11.0 +/- 4.54 mm). We failed to notice any statistically significant difference with regards to CO, coracoid process and lesser tuberosity morphology between the two groups of patients. Conclusion: MRI assessment of CHD can be useful in identifying patients at risk of having subscapularis lesion and coracoids impingement.