Leonardo da Vinci and the body beautiful

Leonardo da Vinci's pioneering anatomical studies are now on show at the Queen's Gallery. Genius is the only word for them, says Adrian Hamilton

We've had Leonardo the painter at the National Gallery.

Now it is back to Da Vinci the scientist with a show of his drawings at the Queen's Gallery. Not just any show but an almost complete exhibition of his anatomical studies, on which he spent a lifetime's observation and which, happily, entered the royal collection as a single set in the 17th century.

Totalling 100, they are simply magnificent, endlessly fascinating in their detail, continuously probing in their exploration of the workings of the human body and always lucid in their presentation. It's become a little too simple to separate this great Renaissance master into artist on the one side, the man who painted the Mona Lisa, and observer on the other, the draughtsman who invented war machines and dissected frogs and monkeys to learn their mechanics.

But Leonardo didn't see it that way. Neither should we. He aimed, with an ambition that seems impossible today, to embrace the whole universe with a study that could discover its rules and delineate its principles. Drawing and painting were the means to an end that was finally beyond any man's reach. The result was that Leonardo, always the perfectionist, completed only some 18 paintings before his death at 67 and, while he made thousands of sketches (over 5,000 survive), he never produced the treatises on anatomy or painting that were to communicate them to the public. For one of the most dedicated and prolific of all artists his final achievement was surprisingly small.

But what paintings and what drawings. Genius is a much overused word. In Leonardo's case, it is the only one that fits. His was a mind of extraordinary breadth and an eye of astonishing precision . He could not finish a bad painting or draw a weak line. His graphic works are no mere addendum to his painting. With them you enter a mind at work covering everything from mechanics to flight, geology and botany. With the anatomical drawings in the Queen's collection you follow that mind through a single passionate theme, man as the perfection of nature.

The works divide into two periods. In the first, from 1485-90, Leonardo, then in Milan, was working largely from external observation of the human body, the strain of muscles and veins in action and the structure of skulls and bones. The operations of blood and organs within the body he took mostly from the dissection of animals. It wasn't that the Church didn't allow it it was just that he had little opportunity.

Nonetheless, Leonardo, with his belief that all creation was part of a universal plan, was able to take such information as he had to a surprisingly sophisticated view of the workings of the body. He starts, as the show begins, with a wonderful series of metalpoint drawings on blue paper of a bear's foot and a magnificent male figure showing the principal veins and organs as received wisdom had them. With his careful handwriting, written in mirror reverse from left to right (Leonardo was left-handed), he attempted to describe blood flow and reproduction with a mind always testing theory with the evidence he actually found in examining bone and tissue from the living and the dead.

In the second phase, from 1504 to around 1512-13, a period when he had returned to Florence and was shuttling back and forth to Milan, and he had readier access to human dissection. He claimed he did some 30 dissections himself and it shows. His notes become more detailed, his drawing more penetrating as he sketches the bones and muscles of shoulder, neck, leg and foot and maps out the veins and tendons of man's moving parts. Although he never quite broke away from the traditional view of blood circulation as a distribution of life in which blood was finally consumed, he came close to capturing it in his studies.

All this adds to the interest and to the respect inspired by his anatomical sketches. But to label Leonardo as a proto-scientist of high distinction is to belie the force of these notebooks as works of art. Even in his meanest or roughest sketch, there is a boldness and clarity that is compelling. Whenever he draws the head it is the head of a real person. When he pictures the muscle of the torso or the leg, he adds red chalk to pen and ink to give it presence. His sketch of the human foetus in the womb is justly famous, but to view the page in which he depicts the curled foetus from different angles, together with the pubis, just takes you breath away. His notes concern the precise way how the unborn child can fit in such a restricted space and the workings of the muscles around the uterus. But step back from the writing and the accompanying explanation, and you view a grouping of figures fleshed out with red and black chalk that are little masterpieces in their own right. He does the same with a remarkable group of drawings, The Superficial Anatomy of the Shoulder and Neck, carefully finished as if for publication in engraved form. Not satisfied with just illustrating tendon and muscle, he models the upper torso with confident hatching of pen with wash over black chalk and gives the head the face of a real man, broken nosed and pensive.

Had he published this work as intended, the curators claim he would have transformed the study of human anatomy. This is no doubt true in the sense that his painstaking examination took him well beyond the confines of conventional belief at the time. Unpublished, they remained forgotten for nearly four centuries. But even without the science this is a show of artistic excitement, beautifully displayed and lit (I've rarely seen a show done better). If you want to witness genius at work you can't miss it.

Leonardo da Vinci: Anatomist, the Queen's Gallery, Buckingham Palace, London SW1 (020 7766 7300; royalcollection.org.uk) to 7 October