Computed tomography in the evaluation of Brown syndrome of the superior oblique tendon sheath

Computed tomographic (CT) findings in 4 patients with superior oblique tendon sheath syndrome (congenital or acquired Brown syndrome) are described. When the inferior oblique muscle moves the eye upward, the superior oblique muscle normally relaxes, while its tendon lengthens and slides freely through the trochlea. In Brown syndrome this process is somehow restricted, which is most apparent during attempts at elevation when the eye is adducted, resulting in an apparent inferior oblique "palsy" (pseudopalsy). Brown syndrome is the most common cause of an apparent isolated limitation of the inferior oblique muscle. CT is a valuable tool in understanding the pathophysiology and management of acquired Brown syndrome, showing thickening and inflammatory changes of the reflected portion of the superior oblique tendon.