(Chapter 32) Footnote 11:

See Galen De usu partium 3.253.10f. (quoted in n. 17 below) and De ossibus 2.775.7-13: “Outside the articulation of femur and tibia lies a cartilaginous circular bone . . . Some call this bone “kneecap,” others the ‘millstone’ [mu/lh].” (tr. Singer 1952, p. 774). Vesalius’ idea that Galen called this a cartilaginous bone “on the outside” (extrinsecus) may be traceable to an error of translation in his Latin version of this work, which was unavailable to him in the original Greek. In the Greek, Kata\ th=j tou= mhrou= kai\ th=j knh/mhj diarqrw/sewj e)/cwqen o)stou=n xondrw=dej e)pi/keitai, the adverb e)/cwqen seems to have been misapplied to the adjective xondrw=dej rather than the verb e)pi/keitai.