Adhesive capsulitis demonstrated on magnetic resonance imaging

Coracoid Process: The Lighthouse of the Shoulder

The coracoid process is a hook-shaped bone structure projecting anterolaterally from the superior aspect of the scapular neck. Surgeons often refer to the coracoid process as the "lighthouse of the shoulder" given its proximity to major neurovascular structures such as the brachial plexus and the axillary artery and vein, its role in guiding surgical approaches, and its utility as a landmark for other important structures in the shoulder. The coracoid also serves as a critical anchor for many tendinous and ligamentous attachments. These include the tendons of the pectoralis minor, coracobrachialis, and short head of the biceps brachii muscles, and the coracoclavicular, coracohumeral, coracoacromial, and transverse scapular ligaments. Consequently, the coracoid and its associated structures are linked to numerous shoulder pathologic conditions. This article will detail the anatomy of the coracoid and its associated structures and review the clinical and radiologic findings of corresponding pathologic conditions in this region with original illustrations and multimodality imaging examples. Highlighted in this article are the coracoclavicular joint, the classification and management of coracoid fractures, subcoracoid impingement, the coracoacromial arch and subacromial impingement, the coracohumeral ligament and the biceps pulley, the coracoclavicular ligament and its surgical reconstruction, adhesive capsulitis, the suprascapular notch and suprascapular notch impingement, subcoracoid bursitis, coracoid transfer procedures, and coracoid tumors. A brief summary of the pathophysiology, potential causes, and management options for each of the pathologic entities will also be discussed. ^©RSNA, 2016.

An MRI study of symptomatic adhesive capsulitis

Background

Appilication of MR imaging to diagnose Adhesive Capsulitis (AC) has previously been described. However, there is insufficient information available for the MRI analysis of AC. This study is to describe and evaluate the pathomorphology of the shoulder in Asian patients with AC compared to healthy volunteers.

Methodology/Principal Findings

60 Asian patients with clinically diagnosed AC and 60 healthy volunteers without frozen shoulder underwent MRI of the shoulder joint. All subjects who were age- and sex-matched control ones underwent routine MRI scans of the affected shoulder, including axial, oblique coronal, oblique sagittal T1WI SE and coronal oblique T2WI FSE sequences. Significant abnormal findings were observed on MRI, especially at the rotator cuff interval. The coracohumeral ligament (CHL), articular capsule thickness in the rotator cuff interval as well as the fat space under coracoid process were evaluated. MRI showed that patients with adhesive capsulitis had a significantly thickened coracohumeral ligament and articular capsule in the rotator cuff interval compared to the control subjects (4.2 vs. 2.4 mm, 7.2 vs. 4.4 mm; p<0.05). Partial or complete obliteration of the subcoracoid fat triangle was significantly more frequent in patients with adhesive capsulitis compared with control subjects (73% vs. 13%, 26% vs. 1.6%; p<0.001). Synovitis-like abnormality around the long biceps tendon was significantly more common in patients with adhesive capsulitis than in control subjects. With regards to the inter-observer variability, two MR radiologists had an excellent kappa value of 0.86.

Conclusions/Significance

MRI can be used to show characteristic findings in diagnosing AC. Thickening of the CHL and the capsule at the rotator cuff interval and complete obliteration of the fat triangle under the coracoid process have been shown to be the most characteristic MR findings seen with AC.