Jean Francois Fernel (1497-1558) was a French physician who introduced the term "physiology" to describe the study of the body's function. He was the first person to describe the spinal canal. The lunar crater Fernelius is named after him. His mathematical and astronomical studies included: Cosmotheoria (1528) determination of a degree of arc of the meridian, Monalosphaerium(1526), and De proportionibus (1528).