Clinical History:
This is a 26-year-old female with no history of trauma, who presents with left shoulder pain.


MR Technique:
3.0 T scanner (Siemens Verio) using a shoulder array coil after administration of diluted intra-articular contrast, which included 0.2 ml of gadolinium chelate. Image 1: axial T1-weighted turbo spin echo image with fat suppression (320 matrix, TR/TE 763/23, scan time 2 min 25 sec, slice thickness 3 mm); Image 2: coronal T1-weighted turbo spin echo using parallel imaging with a factor of 2 with fat suppression (TR/TE 731/21 ms, scan time 3 min 35 sec, slice thickness 3 mm); Image 2: sagital T2-weighted turbo spin echo (320 matrix, TR/TE 4080/82 ms, scan time 4 min 2 sec, slice thickness 3 mm).

Imaging Findings:
The acromioclavicular joint demonstrates an os acromiale (Images 1, 2). The acromion and os acromiale are low-lying in relation to the clavicle (image 3), with significant narrowing of the subacromial outlet. The undersurface of the acromion is flat, Bigliani type I