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Would the fetus drawn by Leonardo da Vinci have delivered by the breech?
  1. Andrew Macnab1,2
  1. 1 Stellenbosch Institute for Advanced Study, Matieland, South Africa
  2. 2 Paediatrics, The University of British Columbia Faculty of Medicine, Vancouver, British Columbia, Canada
  1. Correspondence to Professor Andrew Macnab, Stellenbosch Institute for Advanced Study, Matieland 7600, South Africa; ajmacnab{at}

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Discovery consists of seeing what everybody has seen and thinking what nobody has thought.

Albert Szent-Györgyi (1893–1986), Nobel Laureate in Physiology

A respected mentor’s ‘voice from the past’ taught me a lesson probably familiar to many of us, that when we ensure that what we publish is accurate, we enable others in the future to add to our findings in the light of new knowledge. I doubt Leonardo da Vinci was taught this premise, but it does in fact apply; even almost 500 years on, there are things we can add by observing the detail contained in his extraordinary anatomical drawings.

More than 600 of Leonardo’s drawings are currently housed in the Royal Library at Windsor,1 including 240 illustrations of the human body that are accompanied by over 13 000 words of notes. Many of these drawings are regularly reproduced, as I did, when I recently used ‘The foetus in the womb; sketches and notes on reproduction’ (figure 1) as the cover illustration for a book ‘by gracious permission of Her Majesty Queen Elizabeth II.’ Leonardo described this small chalk and ink study as ‘The infant in the womb showing the foetus in the breech position.’2 It dates from circa 1511, and shows a human fetus lying inside a uterus dissected by Leonardo following surgical exposure within a cadaver.3 Although never published in Leonardo’s lifetime, it is probably the best known illustration of its kind, and almost certainly the first in history to correctly portray the fetus in its proper position within the womb.

Figure 1

Leonardo’s iconic sketch ‘The foetus in the womb’ image (RCIN 919102). Royal Collection Trust/©Her Majesty Queen Elizabeth II 2019. Reproduced with permission as the cover illustration for a book.

Contrary to common belief, human dissection was not forbidden in Leonardo’s time,1 but the challenge was acquiring the bodies; in this regard, Leonardo’s interest was facilitated by his association with Marcantonio della Torre, an eminent anatomist and professor at the University of Pavia, up to the time of his death in the plague of 1511.1 As explained by Peter Dunn in ‘Perinatal lessons from the past,’ Leonardo’s artistic skill was combined with remarkable powers of observation.4 Through his knowledge of perspective and experiments with techniques using cross-section, rotation and multiple angles, his sketches combine amazing accuracy and clarity.3–5 As a result, as Leonardo describes6:

The human body will be demonstrated to you just as if you had the natural man before you. The reason is that if you want to know thoroughly the anatomical parts of man you must either turn him or your eye in order to examine him from different aspects, from below, from above, and from the sides, turning him round and investigating the origin of each part; and by this method your knowledge of natural anatomy is satisfied.

Dunn’s opinion that Leonardo is arguably the greatest anatomist of all time is an echo from an earlier age when another great anatomist, William Hunter, was shown Leonardo’s anatomical sketches at Windsor in 1778 by the King’s librarian, and wrote7:

I expected to see little more than such designs in anatomy as might be useful to a painter in his own profession. But I saw, and indeed with astonishment, that Leonardo had been a general and deep student. When I consider what pains he has taken upon every part of the body, the superiority of his universal genius, his particular excellence in mechanics and hydraulics, and the attention with which such a man would examine and see objects which he has to draw, I am fully persuaded that Leonardo was the best anatomist, at that time, in the world, and certainly the first man, we know of, who introduced the practice of making anatomical drawings.

In defining his anatomical drawing of the fetus, Leonardo correctly describes his sketch as showing ‘the infant in the womb in the breech position’. The concept of breech presentation and practical realities of vaginal delivery by the breech were known by Leonardo’s time. Indeed, techniques to facilitate obstructed delivery were practiced that used internal and external manipulation to achieve a footling presentation which then allowed traction on the legs to deliver the fetus.8 But would this fetus have remained in the breech position until term, or could she/he still have rotated to become a cephalic presentation?

What was the gestation of the fetus? Obviously, the gestation at the time of Leonardo’s dissection is relevant as a fetus only adopts the position from which delivery will occur between the 32nd and 36th week of pregnancy. But, even though he had a stated interest in ‘what it is that forces it (the foetus) out of the mother, and for what reasons it sometimes comes out of the mother’s womb before the due time,’ Leonardo himself only describes a postmortem of a pregnant woman, with no mention in his notes on her cause of death, parity or when she might have conceived.3 4 Neither is there any indication that he weighed the fetus or compared it in size to other newborn infants. Hence, the parameters of due date and fetal weight that conventionally guide assessment of gestation are lacking. In consequence, later observers have proved undecided, having variably described his sketch as being that of a 5-month fetus in the breech position,7 a mid or late trimester pregnancy,9 or a fetus at term.5

However, neonatologists have long recognised that physical examination of newborn infants reveals evidence indicative of differing levels of maturity, and, since the mid-1960s, accurate classification has been made based on the development of certain external physical characteristics which correlate with gestational age10; systems today continue to use physical criteria combined with neurological maturity.

In his small drawing (30.4×22 cm), made with red and black chalk and pen and ink, Leonardo accurately illustrates the anatomy, posture and many physical characteristics of the fetus, including structural details of a well-formed ear and the presence of skin creases extending across the entire sole of the foot (figure 2). In a systematic review and meta-analysis assessing the diagnostic accuracy of scores to assess neonatal gestational age, breast size, plantar skin creases, ear form/firmness and skin texture had the highest median correlation coefficients in the 12 studies based on physical criteria.10 The breasts in Leonardo’s fetus cannot be seen, nor can the skin texture be realistically evaluated. However, as Leonardo said “my configuration of the human body will be demonstrated to you just as if you had the natural man before you.”6 So, with two of the four physical characteristics deemed most reliable clear to see, the probability is that if the fetus he depicts was to be newly born today, these physical criteria would classify the infant’s gestation to be between 36 and 40 weeks of gestation.10

Figure 2

An enlargement from the sketch ‘The foetus in the womb’, where Leonardo illustrates the fetal position and captures in detail the physical features of the ears and feet.

Hence, because of the accuracy of Leonardo’s anatomical masterpiece, just as my mentor said, ‘new’ knowledge can be applied that adds information to what Leonardo’s groundbreaking illustration already tells us. Because application of validated criteria for assessment of gestational age now indicates that Leonardo’s fetus was at or close to term, not only was he correct that this was a breech presentation, we can also add that in all likelihood the infant would have gone on to have been a vaginal breech delivery had the mother survived.

Discovery consists of seeing what everybody has seen and thinking what nobody has thought.



  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.