Biceps tendon dislocation: evaluation with MR imaging.

The magnetic resonance (MR) images from six patients with biceps tendon dislocation--two in whom it was surgically proved and four in whom it was suspected--were retrospectively evaluated. The dislocated tendon can be identified medial to the bicipital groove, best seen on the axial and oblique coronal and sagittal images. Associated abnormalities of the biceps tendon include thickening (n = 3), high signal intensity (n = 3), and surrounding fluid (n = 4). The factors thought to contribute to dislocation can also be well seen on MR images. These include abnormal shape of the bicipital groove (n = 2), disruption of the coracohumeral ligament (n = 6), disruption (n = 4) and thinning (n = 1) of the subscapularis tendon, and supraspinatus tendon tear (n = 4). Since MR imaging is becoming the modality of choice for the evaluation of shoulder derangements, familiarity with the appearance of biceps tendon dislocation on MR images is important.