Recto: three studies, one on a larger scale, of a man's right arm and shoulder, showing muscles; three studies of a right arm; a diagram to illustrate pronation and supination of the hand. Verso: three drawings showing a deep dissection of the muscles of the shoulder region; two studies of the muscles of the shoulder and right arm; a diagram of the respiratory muscles; a skeleton of a left foot with leg bones; notes on the drawings. Leonardo’s greatest scientific researches were in the field of anatomy. He dissected around thirty corpses during his career, and made many observations far in advance of his time. Here he studied the muscles of the shoulder and arm and the bones of the foot, commenting on the structures shown in his typical mirror-writing. Leonardo intended to write a treatise on anatomy, but this was never completed, and his astonishing drawings remained little known until modern times.