(Chapter 15) Footnote 91:

Movement around an infinite number of axes passing through the head of the humerus or femur, with principal axes being (1) extension and flexion around the transverse axis, (2) adduction and abduction around an anteroposterior axis, and (3) laterial and medial rotation around a vertical axis; in the movement of circumduction, the arm or hip swings around the side of a cone, the apex of which is in the shoulder or hip joint.