A sinus tract
is an abnormal channel leading from within bones
or other structures to the skin
surface; sometimes this type of passageway is termed a fistula
Sinus tracts may form after an infection or as a means of decompression of a synovial joint in rheumatoid arthritis or classic fistulous rheumatism.
In septic arthritis, MR imaging may reveal abnormalities such as fluid-filled channels, sinus tracts and fistulae.
Sinography represent a diagnostic imaging method involving opacification of a sinus tract, which may provide information that influences the choice of therapy. Concomitant CT scanning may lead to better delineation of the sinus tract. Sinography in association with fluoroscopy is also employed in evaluation of pressure sores when extent of bone infection is uncertain.