"Buffalo chest" and the American bison

This week while browsing the Oxford University Press blog, I encountered the image shown above - a painting (George Catlin, 1844) of a Native American hunter preparing to bring down a bison with a bow and arrow.  The scale of the painting is a bit off, but the activity depicted is well known; the immense and otherwise robust American bison was uniquely susceptible to death from a simple arrow, or even from a penetrating chest wound from a simple lance.

This unusual susceptibility also contributed to the wholesale slaughter of bison herds when Europeans arrived with firearms.  This old photo (via) from the 1870s shows an unbelievably immense pile of bison skulls:

These iconic and magnificent animals were killed in part to provide meat to workers on the transcontinental railroad, in part to prevent large bison herds from interfering with the progress of the trains, and also as part of a concerted effort by settlers to deprive the Native Americans of one of their principal food resources.  Discussion and additional photos at Rare Historical Photos.

But back to the biology.  The "susceptibility" I mentioned earlier arises from the fact that North American bison have a single pleural space in the chest.  Most mammals (humans included) have separate pleural spaces in the left and right chest.  A penetrating injury or rupture of lung tissue will lead to leakage of air (a pneumothorax) and impaired ventilatory function, but is typically not lethal.  When humans have a single pleural space either as a congenital defect or as a result of previous thoracic surgery, they are said to have a "buffalo chest" as shown in this example:

The PA radiograph shows bilateral pneumothoraces, both of which were relieved by the insertion of a chest tube into just one hemithorax (case report at the Journal of Thoracic Disease).