The terms track and tract are commonly mixed up in radiology and medicine (and often English more generally).

Track

In medicine, track refers to an artificially created path through something, a typical example being a "needle track", which is the narrow channel formed when a needle is inserted into and withdrawn from tissue. The path of a parasitic worm through the body is also called its track. The exception is "surgical tract", which is more commonly used than "surgical track".

Tract

A tract is usually used as an anatomical term referring to:

• a bundle of nerve fibers, e.g. corticonuclear tract

• a series of organs collectively providing a common function, e.g. digestive tract, respiratory tract

• others, e.g. portal tract

Although the meanings of track and tract are distinct, their similar spellings and the fact that they both refer to structurally similar entities means that they are often confused. This is not helped by several publications using the wrong term, such that "needle tract" has appeared in several article titles in the peer-reviewed literature ^3-6.

The water is also slightly muddied since "sinus tract" is the correct term for the pathologically formed path in some inflammatory conditions, which resembles a fistula but is open at one end only. This can result in the correct yet potentially confusing phrase that "the pus tracks along the sinus tract." The track formed by a fistula is also - correctly - called a fistulous tract.

History and etymology

Despite their superficial similarity in spelling, track and tract have different and unrelated etymologies ⁷. 

"Track" is first recorded in the late 15^th century as a mark left by something, from the Middle French "trac", itself of unclear origin, perhaps a Germanic source. It may be related to the Dutch term "trek" which ultimately gives us the modern English word of the same spelling ⁷.

Conversely, "tract" is derived from the Latin word "tractus" which means - somewhat ironically - track! Tractus comes from the verb "trahere" meaning to pull or draw ⁷.