Back in the day, motor vehicles had to be started by hand. Within a car's engine, the up-and-down motion of pistons (produced by igniting a fuel-air mixture) is converted into rotational motion via a crankshaft. When starting up an engine, the crankshaft has to be turned by external means in order to get the conversion going. Prior to the introduction of starter motors, this was usually accomplished by inserting a removable crank into the end of the crankshaft and giving it a couple of turns. Occasionally, a backfiring engine would slam the crank backward into the palm of the person doing the cranking, sometimes twisting their wrist into an unnatural position. The resulting injuries (usually a fracture of the distal end of the radius) were collectively known as chauffeur's fracture, since chauffeurs tended to be prone to them (seeing as they did a lot of hand cranking as part of their job).
|A cowboy hand cranking a car (Source)|
A second type of injury associated with hand cranking was called chauffeurs' knee. This was an inflammation of the right knee brought about by repeatedly having to kneel to turn the engine crank of a car. I'm guessing it's a form of prepatellar bursitis, also seen in kneeling-heavy jobs such as laying carpet or scrubbing floors.
According to an article I unearthed, being hit by a flying detachable rim was all the rage in 1910. At this time, inflating a car wheel involved pumping air into an inner tube lying between a tire and a rim. Rims were sometimes detachable, making it easier to switch tires. These rims were held together by a locking device, which could be compromised if it was held together by a worn screw or wasn't put together properly. In this case, a blow out of the inner tube (e.g. while filling it) could send the rim flying off at high speeds. Being struck by a rim could mean anything from a badly bruised leg to a fatal head wound.
Car exhaust includes carbon monoxide, a gas capable of poisoning people by disrupting the ability of their blood to carry oxygen. As motor vehicles became more popular, people who didn't realize the danger of running them in poorly ventilated spaces started getting sick. Enough people started dying from this particular form of carbon monoxide poisoning that the press came up with a specific term for it: petromortis. This somehow failed to catch on.
Albaugh RP. 1917. Gasoline engine exhaust-gas poisoning. American Journal of Public Health 7(8):664-666. [Full text]
Cherniack MG. 1992. Diseases of unusual occupations: An historical perspective. Occupational Medicine 7(3):369-384.
Emerson ML. 1911. Automobile accidents from detachable rims. California State Journal of Medicine 9(7):298. [Full text]
Stephens P. 1923. So-called chauffeur's fracture. California State Journal of Medicine 21(3):115-117. [Full text]
Winterberg WH. 1912. Some remarks on so-called "automobile fractures." California State Journal of Medicine 10(2):63-64 [Full text]