During the latter part of the 1480s, Leonardo dissected the left hind leg of a bear. At that time bears were common in the mountains of Italy; they were hunted for sport and kept in captivity for entertainment, and Leonardo could thus easily have obtained a specimen for dissection. His particular interest in the animal was probably due to its plantigrade gait – like humans, bears walk with their feet flat on the ground (digitigrade animals such as dogs and cats walk on some portion of the digits, and unguligrade animals such as horses or cattle walk on the tip of a digit, usually in the form of a hoof). Leonardo’s dissection would therefore have given him an insight into the anatomy of the human foot at a time when he had little access to human material.

The principal drawing here shows the bones, muscles and tendons of the lower leg and foot of a bear, in a lateral or outside view - a more finished version is at RCIN 912372 (see that entry for a full discussion of the anatomy). Set into the sheet of paper is a smaller fragment, probably cut by Leonardo's heir Francesco Melzi from another sheet, with a study of the large toe from the medial side (inside).The relationship of the brevis and longus tendons is studied in detail, with the longus tendon passing through a bifurcation in the (reduced) brevis tendon - Leonardo was to pay particular attention to that feature when he found it in the human hand twenty years later (see 919009r).

Text adapted from M. Clayton and R. Philo, Leonardo da Vinci: Anatomist, London 2012, no. 8.