Trolley Track Sign

A term for the combination of the dagger sign—a single central vertical radiodense line caused by ossification of the interspinous and supraspinous ligaments—and the railroad sign—a pair of lateral vertical linear lines—caused by ossification of the apophyseal joints. The three vertical ossified lines together make up the trolley-track sign and are seen on AP view in patients with ankylosing spondylitis
References in periodicals archive ?
The trolley track sign derives from the 2 lateral lines of ossification representing the apophyseal joint capsules, and the dagger sign from the central line of ossification visible on the AP view.
In thoracic (Picture 1) and lumbosacral (Picture 2) graphs, marked squaring in her vertebras, shiny corners, symmetric syndesmophytes, bamboo spine, trolley track sign, osteoporosis and left faced scoliosis were observed.
The morphological changes used to assess spinal involvement in x-ray were syndesmophytes, shining corners, squaring, arthritis of the apophyseal joints, spondylodiscitis, bamboo spine and trolley track sign (13).