Leonardo's Anatomical Studies

At a Glance

• SubjectLeonardo's Anatomical Studies
• Artist and contextLeonardo da Vinci (1452–1519) and his Renaissance world
• ImageBones of the arm and leg.

Contents

1. Dissection in Renaissance Italy
2. From the painted surface to the hidden cause
3. The centenarian and a new anatomy of death
4. Architecture for the skeleton
5. Building the hand in layers
6. Nerves, breath and the production of voice
7. What an anatomical drawing can claim
8. Wax, glass, seeds and the aortic valve
9. Rome, accusation and the end of dissection
10. Achievement without the mythology

Dissection in Renaissance Italy

The persistent story that the Church forbade human dissection gives Leonardo a dramatic but false setting. Italian medical schools held public dissections, usually during cold weather, and post-mortem examinations could be performed to investigate a death. Religious authorities did not impose a general ban. The practical limits were access, rank, law, custom, the small supply of bodies and the rapid decay of unrefrigerated tissue. ^[1]

University physicians and surgeons occupied a different institutional position from an artist. Executed criminals supplied some teaching bodies, while hospitals and monasteries could provide other opportunities. An artist might witness a dissection or study bones and flayed figures without receiving permission to conduct a full investigation. Leonardo's growing fame and connections gradually opened doors that were unlikely to have been available to him as a young craftsman.

The conditions were severe. A body decomposes quickly, especially internal organs and brain tissue. Dissection had to proceed in an order dictated partly by decay. Several people might work around the corpse, and a structure could be damaged before it was understood. Leonardo later wrote of needing multiple bodies to trace all the branches of vessels and nerves, because one specimen could not show everything clearly. A finished sheet may therefore combine information gathered at different times.

Animal anatomy helped bridge the gaps. Frogs, dogs, monkeys, horses, cattle and a bear supplied material that could be obtained more readily or used for controlled procedures. Comparative dissection could reveal shared structures and mechanical principles. It could also introduce an animal feature into a supposed human system. Leonardo's anatomy becomes most accurate when the source, species and observation align; it becomes least reliable when analogy silently replaces missing human evidence.

Dissection did not begin with Leonardo. Medieval Italian universities had developed a teaching tradition in which an authoritative text was read while a body was opened and its parts demonstrated. Mondino de' Liuzzi's early fourteenth-century Anathomia became a durable guide. Galen's much older writings supplied an immense physiological and anatomical framework, although Galen's own human evidence had been restricted and animal structures entered the tradition.

The purpose of a university dissection was not necessarily to invite an open contest between book and corpse. It could demonstrate the ordered body described by the text. Apparent disagreement might be attributed to an abnormal specimen, poor preservation or the dissector's mistake. Yet the physical practice created opportunities for correction, and fifteenth-century physicians did not all respond in one way. Leonardo entered an active, changing culture rather than ending a millennium without anatomical observation. ^[19]

Artists formed a related visual culture. The nude model, skeleton, flayed figure and occasional witnessed dissection served the demands of convincing bodies in painting and sculpture. Anatomical knowledge also helped organise academies of art in later generations. Leonardo's difference lay in the extent to which he made the opened body itself a sustained research subject and in the explanatory labour he asked images to perform. ^[19]

His lack of university Latin could be a barrier, but it also changed his relation to established genres. He wrote in vernacular Italian and placed argument beside drawing. He did not simply illustrate a medical lecturer's words. He repeatedly tried to derive functional explanation from what the hand exposed and the eye could follow. That independence should not be romanticised as freedom from sources: technical terms, Galenic physiology, medieval faculty psychology and physicians around him remained essential.

This mixed position explains both conflict and ambition. Leonardo could see an anatomical relation that a conventional diagram omitted, yet struggle to fit it into an inherited account of spirits and organs. He wanted his proposed work to be visually demonstrative and intellectually comprehensive, while lacking a stable place in the university system that produced and circulated medical books.

Florentine artists had long studied the nude, proportion and the way muscles alter the visible surface. Leonardo's drawings of people and animals show intense attention to the pull of a neck, the load on a leg or the bunching of a horse's shoulder. Such observation supports convincing art, but it does not reveal the attachments beneath the skin.

Leonardo increasingly treated outward form as an effect requiring a cause. A bulge on an arm follows the contraction of a muscle; a change in stance redistributes weight through bones and joints; a facial expression depends on structures that move skin. To represent the body truthfully, he wanted to know the mechanism generating the appearance.

This purpose did not remain subordinate to painting. Early organ diagrams already ask about “spirits”, vessels and sensation—subjects that could not be read from a nude model. His proposed anatomy expanded towards the phenomena of life: conception, growth, movement, voice, perception, emotion, ageing and death. The body became a complex natural machine, but never only a machine. Leonardo continued to work within older ideas about soul, vital heat and the hierarchy of faculties even as dissection forced revisions.

The return to anatomy after 1504 probably received energy from the Battle of Anghiari commission. Its central struggle demanded over-life-size bodies and horses twisted under extreme force. Leonardo studied standing and moving men, external musculature and the mechanics beneath violent action. Yet the eventual anatomy campaign outlived the painting. By then investigation had become its own project. ^[1]

The first campaign: bones, nerves and the skull

Leonardo's earliest surviving anatomical work mixes inherited schemes with limited dissection. A diagram of the principal organs and vessels from the later 1480s shows a traditional division: the liver generates venous blood and “natural spirit”, while the heart supplies “vital spirit” through the arteries. The picture is clear and persuasive, but its systems are conceptual inheritance rather than a map derived wholly from a human body. ^[12]

Animal work was more direct. The anatomy of a bear's foot gave Leonardo an intricate example of bones and tendons that he would remember when studying the human hand more than twenty years later. A human leg may have been dissected in Milan during the 1480s. These investigations began to connect structure with action, even though access remained limited.

In 1489 Leonardo obtained a human skull and sectioned it in several planes. The drawings are exact about the hard structure: teeth, sinuses, jaw and cranial cavity. Fine lines project through the head as he tries to establish the routes of the senses and the position of the senso comune, the faculty thought to receive and coordinate sensory impressions. Geometry promises a centre where the lines might meet. ^[3]

The skull could not disclose the soft brain that had once filled it. Leonardo therefore combined a witnessed bony shell with a traditional ventricular psychology. Medieval schemes often arranged three cells behind the eyes, assigning them perception, reasoning and memory. His exquisite presentation makes these hypothetical structures look observed. The episode is a warning against equating realism of style with direct evidence.

Unable to trace the nerves or establish the brain's internal form from the material available, he stopped. The small notebook begun for the skull studies remained largely unused for nearly two decades. The first campaign had produced a method of sectioning and representation, but not the comprehensive explanation of sensation he wanted. ^[3]

Leonardo returned decisively to human dissection in Florence. His best-documented case began with an encounter at the hospital of Santa Maria Nuova, probably in the winter of 1507–08. An old man told him shortly before dying that he was more than a hundred years old and suffered only weakness. Leonardo witnessed what he described as a peaceful death and dissected the body to seek its cause. ^[1]

That decision turns biography into pathology. Instead of treating the corpse as a generic demonstration of normal anatomy, Leonardo related visible changes to age, life and manner of death. He observed narrowed, winding coronary vessels and changes in the arteries. He also drew a small liver and an enlarged spleen, findings now associated with cirrhosis and portal hypertension. His explanations were not modern diagnoses, but the link between an individual history and internal alteration was unusually attentive. ^[4]

The old man's body also made the limits of one specimen clear. Vessels are difficult to follow through collapsed tissue. Leonardo repeatedly redrew their relation to liver, spleen, kidneys, aorta and vena cava, arriving at an ordered arrangement that remained partly incorrect and more regular than a real opened abdomen. The series shows investigation rather than a clean leap from looking to knowing. ^[4]

He compared the old man with a young child, seeking bodily differences between the beginning and end of life. Ageing seemed connected to the narrowing and drying of vessels. The interpretation preserved contemporary ideas about moisture and vitality, but it was grounded in a physical contrast. The autopsy opened the five most productive years of Leonardo's anatomical work.

With better access to human material, Leonardo returned to the problem that had stopped him in 1490. Brain tissue is too soft to hold the shape of its cavities after cutting. Around 1508–09 he devised a procedure borrowed from casting: inject molten wax into the ventricles, allow it to set, then remove the surrounding tissue. The solid wax preserves a negative space as a positive object. ^[5]

The operation turned an invisible, unstable cavity into a durable model. On RCIN 919127, the brain is divided along the midline and opened, while hatched areas indicate the hardened wax. Royal Collection Trust describes this as the first recorded use of a setting injection medium to reveal a body cavity. Its importance lies as much in the transfer of technique as in priority. A procedure familiar from mould-making and sculpture became an anatomical experiment. ^[5]

The resulting form displaced the simple row of three spherical cells. Further dissection showed that nerves did not enter the ventricles in the way the inherited faculty scheme required. Leonardo abandoned parts of the old arrangement. Yet the experiment did not create modern neuroscience. He still sought bodily sites for faculties such as memory and imagination, and his ability to trace fine neural structures was constrained by the tissue and methods available.

Wax injection expresses a recurring principle in his anatomy: when direct sight fails, transform the object so that the relevant relation becomes visible. Cutting, casting, separating, suspending and modelling are ways of asking the body a question.

Pavia and the problem of Marcantonio della Torre

The most coherent musculoskeletal group was made in the winter of 1510–11, probably at the medical school of the University of Pavia. Leonardo had announced an intention to complete his anatomy that winter. Eighteen surviving sheets, now called Anatomical Manuscript A, contain more than 240 drawings of bones, joints and muscles. The body is surveyed with a consistency unmatched elsewhere in his anatomical papers. ^[1]

This campaign is associated with Marcantonio della Torre, a young physician and lecturer who moved between Padua and Pavia. Giorgio Vasari later wrote that they worked together, with Leonardo supplying drawings for della Torre's anatomical learning. The partnership is plausible: university access would help explain the volume of human material, while a physician could provide learned context and terminology.

The surviving evidence does not permit a detailed division of labour. No completed co-authored atlas has been found, and scholars debate the chronology and exact nature of their encounter. Some drawings commonly linked with the partnership continued after della Torre's death in 1511. Treccani notes that even the timing is not entirely secure because Leonardo's documented presence in Pavia was limited. It is therefore safer to describe intellectual and practical collaboration as probable than to assign every sheet to a formal book project between two equal authors. ^{[17] [18]}

Della Torre's early death removed a valuable medical connection, but it did not end Leonardo's anatomy immediately. He continued reproductive and cardiac investigations. The event belongs among several reasons the projected work remained unfinished; it should not become the single explanation.

Leonardo faced a representational problem: a body is three-dimensional, layered and mobile, while paper is flat. Anatomical Manuscript A adapts methods from architecture and engineering to make structure recoverable from images.

The vertebral column on RCIN 919007 appears from the side and front like architectural elevations. Its cervical, thoracic, lumbar, sacral and coccygeal regions are differentiated, and the natural curves are shown rather than forcing the spine into a straight support. An exploded view separates the first and second cervical vertebrae above the third, allowing their fit to be understood. The Royal Collection calls it the first accurate depiction of the spine. ^[6]

RCIN 919012 extends the method to the skeleton. Front, side and rear views establish relationships among thorax, spine, pelvis and limbs. Oblique ribs and the tilt of the pelvic girdle are observed rather than regularised into a symmetrical emblem. This is not principally another exercise in ideal proportion. It is a mechanical survey of articulated supports. ^[10]

Movement enters through repeated positions. Arms rotate; knees flex; feet bear and transfer weight. A joint is not understood merely by listing its parts but by seeing how contact surfaces permit one path and restrict another. Leonardo sometimes bored or cut bones, manipulated them and removed surrounding tissues to isolate the action.

The architectural comparison has limits. Bones grow, vary and join living tissue; they are not stone members. Yet elevation, section and exploded view let a reader reconstruct an arrangement that one picture cannot contain. Leonardo's innovation was not just anatomical accuracy but a visual grammar for communicating it.

Bones provide supports and joints, but muscles turn the articulated frame into motion. Leonardo wanted to know more than a muscle's visible shape. He asked where it begins and ends, along which direction it pulls, how its tendon crosses a joint, which opposing muscle reverses the action and what change appears on the skin.

The approach encouraged him to reduce anatomy to mechanical relations. Tendons behave like cords, bones like levers and joints like constrained pivots. A muscle may act at a distance from the part that moves. The body is not a machine assembled by a human maker, but mechanisms offer a language for analysing its work. Modern scholarship has described these studies as an early encounter between anatomy, mechanics and mathematical biology, while warning that Leonardo's geometric ambitions did not become a complete quantitative biomechanics. ^[22]

He considered the relation between shortening and thickening. When a muscle contracts, its volume appears to remain while its dimensions change; a shorter form becomes broader. This observation helped him connect internal action to surface relief. It also mattered for drawing figures under strain, where a painter must distinguish the shape of active muscle from the relaxed form of a model.

Cadaveric evidence could not supply contraction. Leonardo therefore moved back and forth between the dissected attachment and the living body in a pose. The resulting figure may display a deep muscle while preserving the tension observed through skin. It is a synthetic demonstration: no literal stage of dissection looks exactly like it, but each component answers a different evidential need.

His mechanical language clarified systems while sometimes over-simplifying them. A thread diagram preserves line of pull but removes width, varying fibre direction and deformation. Lever analogies can isolate torque while neglecting soft-tissue interaction. The value is analytical, not a claim that the living body is reducible to rigid parts.

Leonardo's notes often ask for motion to be drawn from several directions. A muscle that appears to travel straight in one view may curve around bone in another. The multiple-view sheet is therefore not redundant illustration. It tests whether a proposed action remains plausible in space.

Building the hand in layers

The hand offered an extreme test because many small bones, tendons, muscles, vessels and nerves occupy a narrow space. On RCIN 919009, Leonardo builds the structure step by step. A skeletal hand establishes the frame. Deep muscles of palm and wrist follow. One layer of flexor tendons is added, then a second. Smaller diagrams show how tendons pass and how fingers bend differently. ^[9]

This order reverses dissection. The dissector removes layers from surface to depth, but the explanatory sequence constructs the hand from inside outward. The reader does not simply witness what appeared on the table; the reader receives a designed account of dependency.

Earlier comparative work re-enters the page. Leonardo had observed in a bear's foot that one tendon passes through a split in another, a relation also present in human finger flexors. Animal dissection here provided a useful preview that human anatomy could confirm. The method is at its strongest when comparison directs attention and the human body then tests it.

The drawings also resist the temptation to treat the hand as a bundle of cords. Bones set leverage, tendons transmit force and muscles act at a distance from the movement they produce. Leonardo's engineering habits help him follow cause through connected parts.

The shoulder is less visibly ordered than a hinge. It combines the scapula, clavicle and humerus with overlapping muscles that stabilise and rotate the arm. Leonardo studied it in deep dissection, surface observation, sequential turning and abstract diagrams.

On RCIN 919001, views progress around a right shoulder from behind and above towards the front. The rotator-cuff muscles and their insertions on the head of the humerus are distinguished. Some final forms are visualised as if living tissue remained active, because Leonardo knew that cadaveric muscles relax and collapse. Direct dissection and observation of the living model are combined rather than confused. ^[7]

RCIN 919003 moves between modelled surface and a “thread diagram”. Muscles are reduced to cords along their central lines of force, so a complex three-dimensional system can be perceived at once. The abstraction removes bulk to preserve attachment, direction and mechanical action. It anticipates the logic of a force diagram without pretending that muscle is literally thread. ^[8]

Abstraction could also harden an error. Leonardo habitually divided the pectoralis major into separate bodies, whereas its fibres form a continuous fan-like muscle. His desire to map distinct directions of pull encouraged the segmentation. The same page can therefore be brilliant as mechanics and imperfect as morphology.

The shoulder and neck sheets demonstrate why “drawn from life” is not one simple category. A contour may derive from a living sitter, the attachments from dissection, and the final stripped figure from visual synthesis. Leonardo makes a body that could not exist in the observed state so that its working relations can be seen. ^{[7] [8]}

Nerves, breath and the production of voice

Leonardo's search for the connection between body and sensation returned in studies of the peripheral nerves. On RCIN 919050, he followed the right vagus nerve beside the trachea and oesophagus towards the stomach, the phrenic nerve towards the diaphragm and the recurrent laryngeal branch back towards the voice box. Several pathways are impressively close to human anatomy. ^[11]

The sheet also contains topographical confusion. Arteries, veins and nerves are placed in the wrong front-to-back relations, and the recurrent branch loops around an inaccurate arrangement of vessels. Leonardo's notes do not hide uncertainty: he instructs himself to examine how the recurrent nerves relate to the trachea and how muscles produce low, middle and high voice.

Voice required more than identifying a nerve. He drew tongue, palate, hyoid, larynx, trachea, bronchi and oesophagus in different relations. The incomplete cartilaginous rings of the trachea prompted a functional explanation: their open rear allows room for food passing through the oesophagus. Anatomy becomes an account of coexistence among systems in a crowded body.

The enquiry did not reach a complete physiology of speech. It shows instead how a question about sound passes through dissection, mechanics, airflow, muscular control and sensation. The body cannot be partitioned as easily as a treatise's chapters.

An anatomical image often claims to represent “the” hand, spine or heart, but every dissection begins with one individual. Leonardo moved between these levels without a modern concept of population variation. He selected a clear form from messy tissue, joined evidence from several bodies and sometimes regularised what he saw.

The centenarian pushed him towards individual pathology. The shoulder sequence used a living form to correct the relaxed dead one. Male bodies were more accessible than female bodies, leaving female organs and pregnancy particularly vulnerable to composite construction. Age, sex, disease, species and preservation condition all affected the evidence.

Leonardo knew that repetition was necessary. One body might show vessels, another muscles; damage in one dissection could be corrected in the next. Yet the surviving drawings rarely provide a case series in a modern clinical sense. They distil selected observations into explanatory forms. Their precision should not be mistaken for statistical generality.

This tension is productive. The image must be specific enough to preserve structure and general enough to teach. Leonardo's solutions—multiple views, labelled leaders, layers and simplified force lines—helped define what a visual anatomy could do, even when his idealisation smoothed away variation.

The compelling finish of Leonardo's sheets can make every line seem equally certain. In practice, he used several levels of claim. Some drawings record a structure exposed before him. Others reconstruct what several dissections imply. Diagrams deliberately simplify. Composite images place systems together that could not remain visible in one stage of an actual procedure. Hypothetical drawings give an inherited theory a bodily form.

He sometimes signalled these differences through style and sequence, but not through a modern legend. Text is indispensable. A note may identify an animal source, admit that a point must be checked, or instruct the future author to draw the part again. Without it, a viewer can mistake a question for a conclusion.

Leader lines and labels also make choices. A dense cluster is separated into named paths; a faint structure is emphasised; tissue that obscures a relation disappears. Such intervention is necessary for explanation. “Accuracy” therefore means more than copying appearance. The drawing must preserve the relevant structure while openly departing from the immediate visual field.

Leonardo's best sheets solve this problem through controlled transformations. The spine is rotated into orthogonal views. The hand is rebuilt by layers. Muscle mass becomes a thread to expose force. A cavity becomes wax. Blood flow becomes seeds in water. Each method answers a particular question, and each has a known cost in realism.

This is why the drawings remain important beyond the correctness of individual labels. They make visible the reasoning between a body and a claim about it. Even where the conclusion is wrong, the page may reveal exactly how observation, analogy or graphic construction produced it.

Reproduction: from inherited conduits to observed structures

Leonardo's early reproductive drawings show how authoritative ideas could become convincing pictures. In a sectioned man and woman of about 1490–92, impossible ducts travel from spinal cord and heart into the penis to carry “animal” and “spiritual” components, while another vessel links uterus and breast so retained menstrual blood can become milk. He could never have observed the couple in the state shown. The bodies visualise a philosophical account of conception. ^[13]

Later access improved the anatomy but did not remove every inherited belief. Dissection of a gravid cow provided membranes, uterus and cotyledonary placenta. The famous fetus sheet of about 1511 places a plausibly observed human fetus in a uterus whose placental structures are largely bovine. Notes examine nourishment, breathing, membranes and maternal-fetal relation while also retaining contemporary ideas about shared sensation and maternal imagination. ^[14]

The dedicated study of The Fetus in the Womb requires a close reading of both sides of that sheet. Within the wider anatomical programme, its importance is methodological: Leonardo tried to understand development through rare human evidence, accessible animal material and theory. The result is neither pure observation nor fantasy. Species boundaries must be restored before its achievements can be assessed.

Female dissection was especially difficult to obtain. A large female anatomical figure combines organ systems and information from different sources, some correct, some schematic. Leonardo's intention to compare male and female bodies was much larger than the evidence he could gather.

The final great campaign, from about 1511 to 1513, concentrated on the heart. Much of the detailed work used ox hearts, which provided robust, obtainable material and resemble the human heart in important respects. Leonardo examined chambers, muscular walls, papillary muscles, chordae, coronary vessels and valves. He rejected the old idea that the heart was not a muscle and understood its contraction as active mechanical work. ^[1]

His language could still carry older physiology. The lungs were thought to cool the heart, and invisible pores in the interventricular septum were expected to let blood pass from right to left. He retained a separation between arterial and venous systems even while recognising that the heart stood at the origin of both. These assumptions prevented a model of blood circulating continuously around the body. ^[12]

The phrase “discovered circulation” is therefore wrong. Leonardo understood flow through parts of the heart and the one-way action of valves with extraordinary depth. He came close to a different overall system but did not deduce the closed circuit later demonstrated by William Harvey. Royal Collection Trust states this boundary plainly. ^[12]

The failure was not due to lack of observation alone. A comprehensive circulation required revising several connected beliefs at once: septal pores, separate systems, pulmonary function and the fate of blood in the extremities. Local accuracy can coexist with a mistaken global model.

Leonardo's most elaborate cardiac experiment began by adapting the brain-casting method. He injected wax into the left ventricle and aorta of an ox heart, capturing the shape of the widening just beyond the valve. From that form he designed a glass model. Water mixed with grass seeds could then make flow paths visible. ^[15]

The seeds revealed rotating eddies in the aortic sinus. Leonardo reasoned that these vortices help the three cusps move towards closure when forward flow slows after a heartbeat. On RCIN 919116, twenty drawings and more than 1,500 words pursue the event in minute detail. Modern flow imaging confirms the importance of sinus vortices in valve behaviour, though present physiology should not be read back into every part of his account. ^[16]

The experiment joins several crafts. Wax casting captures internal geometry; glassmaking produces a transparent model; hydraulics supplies the analysis of vortices; seeds act as tracers. The living event is not observed directly inside a beating heart. It is reconstructed through a sequence of material translations.

Those translations introduce assumptions. A rigid glass model is not contracting tissue, water is not blood and omitted valve cusps alter the system. Leonardo nevertheless isolated a relation that dissection alone could not display: geometry shapes flow, and flow helps govern closure.

He also entertained a sphincter-like action in the valve and continued to draw supposed septal pores. His account deserves admiration because it exposes a difficult mechanism, not because every component was modern. The abrupt end of the heart studies leaves the conflict unresolved. ^{[15] [16]}

Notes, images and an intended treatise

Leonardo's anatomy cannot be understood from drawings alone. The surrounding mirror-written notes identify structures, question functions, order new observations and tell the future author how to present a result. On the shoulder and arm sheets, many notes concern what still needs investigation or how a subject might be depicted. They are working instructions rather than captions to a completed atlas. ^[2]

He imagined a publication in which images would replace the limitations of verbal description. Several views could give a “complete” knowledge that no single dissection or paragraph supplied. He considered order: bones before muscles, attachments before action, parts before the whole. He wrote prospective introductions and claimed that his many drawings could teach more concisely than existing writers.

Anatomical Manuscript A came closest to a coherent section. Its eighteen sheets survey much of the musculoskeletal system at a consistent level. Yet even this group is not a press-ready book. Elsewhere, studies of organs, reproduction, brain and heart remain distributed across papers of different dates and states. Definitions shift, proposed chapters proliferate and new evidence disrupts older schemes.

Perfectionism is part of the explanation, but the research problem itself kept expanding. To explain a muscle meant explaining its attachment, line of pull, antagonist, nerve supply and effect on the living surface. To explain the heart meant explaining blood, lungs, vessels, heat and flow. Completion receded as understanding grew.

Leonardo moved to Rome in 1513 and attempted to continue at the hospital of Santo Spirito near the Vatican. According to the Royal Collection account, he was accused of sacrilegious practices and prevented from conducting further dissections. The episode was a real obstruction, probably intensified by conflict with a German mirror-maker in his household who denounced him. ^[1]

It does not establish a universal religious ban. Leonardo had already dissected in hospital and university settings, and medical dissection continued in Italy. The problem in Rome concerned his particular access, relationships and accusations. Turning it into a lifelong clandestine struggle against “the Church” erases the institutions that had enabled the work.

After moving to France in 1516, Leonardo did not resume a sustained anatomical campaign. Yet the papers remained a coherent part of the knowledge he presented to important visitors. On 10 October 1517, Cardinal Luigi d'Aragona and his secretary Antonio de Beatis visited Leonardo at the Château de Cloux. De Beatis recorded that they saw anatomical demonstrations in pictures covering limbs, muscles, nerves, veins, joints and viscera in male and female bodies. He also described drawings and vernacular notes that Leonardo intended to organise for publication, including an anatomical treatise. ^[23]

The encounter is unusually strong evidence because it records what a visitor saw and what Leonardo said about the material near the end of his life. It shows that the anatomy was neither forgotten loose paper nor merely reconstructed as a project by modern editors. Leonardo displayed it as an extensive corpus and still envisaged publication. It does not show that a finished book existed: de Beatis's language is not wholly unambiguous, and the surviving sheets retain incompatible dates, revisions and degrees of completion. Leonardo died in 1519 with the project still private. ^{[2] [23]}

Leonardo left his papers to Francesco Melzi. Early biographers knew of the anatomical drawings, but their dense mixture of image, mirror script and unfinished organisation was difficult to use. Around 1580, Pompeo Leoni acquired large quantities of the papers from Melzi's family and mounted more than 500 drawings, including the known anatomical material, in a great album. ^{[20] [21]}

The album reached England and belonged to the Earl of Arundel by about 1630. It entered the Royal Collection later in the seventeenth century, probably under Charles II, and is documented there by 1690. During the nineteenth century, the sheets were removed from Leoni's binding for preservation and display. The empty binding survives as an object in its own right. ^[20]

This secure survival did not equal circulation among anatomists. Individual viewers saw the drawings, and William Hunter examined them in the eighteenth century, but comprehensive publication and translation came only in the late nineteenth century. Anatomical Manuscript A received its modern name through an 1898 facsimile edition. ^[2]

By then European anatomy had been transformed through printed works, teaching and repeated public correction. Andreas Vesalius's De humani corporis fabrica appeared in 1543, twenty-four years after Leonardo's death. Leonardo's unpublished studies did not supply its foundation. A historically meaningful contribution requires a route by which knowledge enters other work; brilliance held in a private album cannot have the same contemporary effect as a widely read book.

Achievement without the mythology

Leonardo's anatomy remains extraordinary because it joined three kinds of skill. He could dissect manually, reason about the structures he uncovered and design images that made those structures intelligible. The spine, shoulder, hand and aortic valve are not merely beautiful records. They are analyses performed through cutting, turning, layering, casting and abstraction.

His work also preserves its limits unusually clearly. Traditional ventricular faculties occupy an early skull. Animal organs enter human diagrams. An accurately observed recurrent nerve sits in an incorrect topography. A brilliant valve model coexists with imaginary septal pores. The lungs still cool the heart, and blood does not complete a circulation. Leonardo's eye corrected authority repeatedly, but it did not release him all at once from the physiological system in which he had learned to think.

Nor was he an isolated artist stealing bodies in defiance of a hostile age. Hospitals, medical schools, physicians, patrons, assistants and the availability of animal material made the research possible. His probable exchange with Marcantonio della Torre connected visual and university anatomy, even if its precise product cannot be reconstructed. The body of work arose through access and collaboration as well as individual persistence.

Had the anatomical project been completed and published, it might have become a major intervention in sixteenth-century anatomy. It was not. Its historical importance now lies in what the surviving papers show: an investigator learning to make hidden structure visible, demanding that inherited claims meet dissection, and inventing a visual language capable of explaining the body in space and motion. That achievement does not require an imaginary discovery of circulation or a forbidden laboratory. It is already present in the evidence of the pages.

Continue exploring Leonardo

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• Leonardo and Science

Frequently Asked Questions

References

1. Martin Clayton, “Leonardo's Study of Anatomy,” Royal Collection Trust. View Source
2. Martin Clayton and Ron Philo, Leonardo da Vinci: Anatomist (Royal Collection Trust, 2012). View Source
3. Royal Collection Trust, “The cranium sectioned; The skull sectioned,” RCIN 919058. View Source
4. Royal Collection Trust, “The heart compared to a seed; The vessels of liver, spleen and kidneys,” RCIN 919028. View Source
5. Royal Collection Trust, “The brain,” RCIN 919127. View Source
6. Royal Collection Trust, “The surface anatomy of the shoulder and arm; The vertebral column,” RCIN 919007. View Source
7. Royal Collection Trust, “The bones and muscles of the shoulder; The superficial anatomy of the shoulder and neck,” RCIN 919001. View Source
8. Royal Collection Trust, “The superficial anatomy of the shoulder and neck; The muscles of the shoulder,” RCIN 919003. View Source
9. Royal Collection Trust, “The bones, muscles and tendons of the hand,” RCIN 919009. View Source
10. Royal Collection Trust, “The skeleton; The muscles of the face and arm, and the nerves and veins of the hand,” RCIN 919012. View Source
11. Royal Collection Trust, “The arteries of the shoulder; The distribution of the right vagus and right phrenic nerves,” RCIN 919050. View Source
12. Royal Collection Trust, “The major organs and vessels,” RCIN 912597. View Source
13. Royal Collection Trust, “The viscera of a horse(?); The hemisection of a man and woman in the act of coition,” RCIN 919097. View Source
14. Royal Collection Trust, “The fetus in the womb; sketches and notes on reproduction,” RCIN 919102. View Source
15. Royal Collection Trust, “The aortic valve,” RCIN 919082. View Source
16. Royal Collection Trust, “Studies of the nerves and muscles, the heart, and optics; Blood flow through the aortic valve,” RCIN 919116. View Source
17. Edgardo E. E. Picardi et al., “Marco Antonio della Torre and Leonardo da Vinci,” Clinical Anatomy 32 (2019), 744–748. View Source
18. Tiziana Pesenti, “Dalla Torre, Marco Antonio,” Dizionario Biografico degli Italiani, Treccani. View Source
19. Nicholas R. Sealy, “Anatomy and academies of art I: founding academies of art,” Journal of Anatomy 237 (2020), 830–841. View Source
20. Royal Collection Trust, “The Leoni binding,” RCIN 933320. View Source
21. Royal Collection Trust, “The drawings,” Leonardo da Vinci: A Life in Drawing. View Source
22. Martin Kemp and Juliana Barone, “Revisiting Leonardo on Muscles: Intimations of Mathematical Biology and Biomechanics,” Biological Theory 18 (2023), 292–303. View Source
23. Laure Fagnart, “‘In uno de li borghi el signore con noi altri andò ad videre messer Lunardo Vinci firentino’: Luigi d'Aragona's visit to Leonardo da Vinci (10 October 1517),” in Pietro C. Marani, ed., L'ultimo Leonardo 1510–1519 (Nomos, 2020), 175–185. View Source

Famous Leonardo da Vinci Artworks

Mona Lisa

The Last Supper

Annunciation

The Baptism of Christ

Adoration of the Magi

Lady with an Ermine

Ginevra de' Benci

Virgin of the Rocks