Question: How many detailed drawing did he have on anatomy?
About the article "Leonardo da Vinci", section "Anatomy".

Candidate passages:
Society and culture.
Anatomy has become a key part of the visual arts.
Basic concepts of how muscles and bones function and change with movement are vital in drawing, painting or animating a human figure.
Many books (such as "Human Anatomy for Artists: The Elements of Form") have been written as guides to drawing the human body anatomically correctly.
Leonardo da Vinci sought to improve his art through a better understanding of human anatomy.
In the process he advanced both human anatomy and its representation in art.
Because the structure of living organisms is complex, anatomy is organized by levels, from the smallest components of cells to the largest organs and their relationship to others. 
As Leonardo became successful as an artist, he was given permission to dissect human corpses at the hospital Santa Maria Nuova in Florence.
Later he dissected in Milan at the hospital Maggiore and in Rome at the hospital Santo Spirito (the first mainland Italian hospital).
From 1510 to 1511 he collaborated in his studies with the doctor Marcantonio della Torre.
""I have removed the skin from a man who was so shrunk by illness that the muscles were worn down and remained in a state like thin membrane, in such a way that the sinews instead of merging in muscles ended in wide membrane; and where the bones were covered by the skin they had very little over their natural size.""
In 30 years, Leonardo dissected 30 male and female corpses of different ages.
Together with Marcantonio, he prepared to publish a theoretical work on anatomy and made more than 200 drawings.
However, his book was published only in 1680 (161 years after his death) under the heading "Treatise on painting".
Among the detailed images that Leonardo drew are many studies of the human skeleton.
He was the first to describe the double S form of the backbone.
He also studied the inclination of pelvis and sacrum and stressed that sacrum was not uniform, but composed of five fused vertebrae.
Leonardo was a physiologist as well as an anatomist, studying the function of the human body as well as examining and recording its structure.
He dissected and drew the human skull and cross-sections of the brain, transversal, sagittal, and frontal.
These drawings may be linked to a search for the "sensus communis", the locus of the human senses, which, by Medieval tradition, was located at the exact physical center of the skull.
Leonardo studied internal organs, being the first to draw the human appendix and the lungs, mesentery, urinary tract, reproductive organs, the muscles of the cervix and a detailed cross-section of coitus.
He was one of the first to draw a scientific representation of the fetus in the intrautero.
Leonardo studied the vascular system and drew a dissected heart in detail.
He correctly worked out how heart valves ebb the flow of blood yet he did not fully understand circulation as he believed that blood was pumped to the muscles where it was consumed.
In 2005 a UK heart surgeon, Francis Wells, from Papworth Hospital Cambridge, pioneered repair to damaged hearts, using Leonardo's depiction of the opening phase of the mitral valve to operate without changing its diameter allowing an individual to recover more quickly.
Wells said "Leonardo had a depth of appreciation of the anatomy and physiology of the body - its structure and function - that perhaps has been overlooked by some.
"Leonardo's observational acumen, drawing skill, and the clarity of depiction of bone structures reveal him at his finest as an anatomist.
However, his depiction of the internal soft tissues of the body are incorrect in many ways, showing that he maintained concepts of anatomy and functioning that were in some cases millennia old, and that his investigations were probably hampered by the lack of preservation techniques available at the time.
Leonardo's detailed drawing of the internal organs of a woman (See left) reveal many traditional misconceptions.
Leonardo's study of human anatomy led also to the design of the first known robot in recorded history.
The design, which has come to be called Leonardo's robot, was probably made around the year 1495 but was rediscovered only in the 1950s. 
Charles Bell was a prolific author.
Shortly after arriving in London, he set his sights on the Chair of Anatomy at the Royal Academy, and, in furtherance of this career goal, he published "Essays on The Anatomy of Expression in Painting" (1806), later re-published as "Essays on The Anatomy and Philosophy of Expression" in 1824.
In this work, Bell followed the principles of natural theology, asserting the existence of a uniquely human system of facial muscles in the service of a human species with a unique relationship to the Creator.
After the failure of his application, (Sir Thomas Lawrence, later President of the Royal Academy, described Bell as "lacking in temper, modesty and judgement"), Bell turned his attentions to the nervous system.
Bell published detailed studies of the nervous system in 1811, in his privately circulated book "An Idea of a New Anatomy of the Brain".
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1318665/pdf/janatphys00211-0151.pdf] He described his experiments with animals and later emphasised how he was the first to distinguish between sensory and motor nerves.
This essay is considered by many to be the founding stone of clinical neurology.
However, Bell's "original" essay of 1811 did not actually contain a clear description of motor and sensory nerve roots as Bell later claimed, and he seems to have issued subsequent incorrectly dated revisions with subtle textual alterations.
Charles Darwin (and others) found in Bell's published views more evidence of his personal ambitions than of proper scientific enquiry.
Nevertheless, Bell's studies on emotional expression, flawed though they were, played a catalytic role in the development of Darwin's considerations of the origins of human emotional life; and Darwin very much agreed with Bell's emphasis on the expressive role of the muscles of respiration.
Darwin detailed these opinions in his The Expression of the Emotions in Man and Animals (1872), written with the active collaboration of the psychiatrist James Crichton-Browne.
Bell was one of the first physicians to combine the scientific study of neuroanatomy with clinical practice.
In 1821, he described in the trajectory of the facial nerve and a disease, Bell's Palsy which led to the unilateral paralysis of facial muscles, in one of the classics of neurology, a paper to the Royal Society entitled "On the Nerves: Giving an Account of some Experiments on Their Structure an Functions, Which Lead to a New Arrangement of the System.
"Bell also combined his many artistic, scientific, literary and teaching talents in a number of wax preparations and detailed anatomical and surgical illustrations, paintings and engravings in his several books on these subjects, such as in his book "Illustrations of the Great Operations of Surgery: Trepan, Hernia, Amputation, Aneurism, and Lithotomy" (1821).
He wrote also the first treatise on notions of anatomy and physiology of facial expression for painters and illustrators, titled "Essays on the Anatomy of Expression in Painting" (1806).
In 1833 he published the fourth Bridgewater Treatise, "The Hand: Its Mechanism and Vital Endowments as Evincing Design".
A number of discoveries received his name:  Bell's (external respiratory) nerve: The long thoracic nerve.
Bell's palsy: a unilateral idiopathic paralysis of facial muscles due to a lesion of the facial nerve.
Bell's phenomenon: A normal defense mechanism—upward and outward movement of the eye which occurs when an individual closes their eyes forcibly.
It can be appreciated clinically in a patient with paralysis of the orbicularis oculi (e.g.
Guillain-Barre or Bell's palsy), as the eyelid remains elevated when the patient tries to close the eye.
Bell's spasm: Involuntary twitching of the facial muscles.
Bell-Magendie law or Bell's Law: States that the anterior branch of spinal nerve roots contain only motor fibers and the posterior roots contain only sensory fibers.  
Leonardo's formal training in the anatomy of the human body began with his apprenticeship to Andrea del Verrocchio, who insisted that all his pupils learn anatomy.
As an artist, he quickly became master of "topographic anatomy", drawing many studies of muscles, tendons and other visible anatomical features.
As a successful artist, he was given permission to dissect human corpses at the Hospital of Santa Maria Nuova in Florence and later at hospitals in Milan and Rome.
From 1510 to 1511 he collaborated in his studies with the doctor Marcantonio della Torre.
Leonardo made over 240 detailed drawings and wrote about 13,000 words towards a treatise on anatomy.
These papers were left to his heir, Francesco Melzi, for publication, a task of overwhelming difficulty because of its scope and Leonardo's idiosyncratic writing.
It was left incomplete at the time of Melzi's death more than fifty years later, with only a small amount of the material on anatomy included in Leonardo's "Treatise on painting", published in France in 1632.
During the time that Melzi was ordering the material into chapters for publication, they were examined by a number of anatomists and artists, including Vasari, Cellini and Albrecht Dürer who made a number of drawings from them.
Leonardo's anatomical drawings include many studies of the human skeleton and its parts, and studies muscles and sinews.
He studied the mechanical functions of the skeleton and the muscular forces that are applied to it in a manner that prefigured the modern science of biomechanics.
He drew the heart and vascular system, the sex organs and other internal organs, making one of the first scientific drawings of a fetus "in utero".
The drawings and notation are far ahead of their time, and if published, would undoubtedly have made a major contribution to medical science.
As an artist, Leonardo also closely observed and recorded the effects of age and of human emotion on the physiology, studying in particular the effects of rage.
He also drew many figures who had significant facial deformities or signs of illness.
Leonardo also studied and drew the anatomy of many animals, dissecting cows, birds, monkeys, bears, and frogs, and comparing in his drawings their anatomical structure with that of humans.
He also made a number of studies of horses.
Leonardo not only studied human anatomy, but the anatomy of many other animals as well.
He dissected cows, birds, monkeys and frogs, comparing in his drawings their anatomical structure with that of humans.
On one page of his journal Leonardo drew five profile studies of a horse with its teeth bared in anger and, for comparison, a snarling lion and a snarling man.
""I have found that in the composition of the human body as compared with the bodies of animals, the organs of sense are duller and coarser...
I have seen in the Lion tribe that the sense of smell is connected with part of the substance of the brain which comes down the nostrils, which form a spacious receptacle for the sense of smell, which enters by a great number of cartilaginous vesicles with several passages leading up to where the brain, as before said, comes down.""
In the early 1490s Leonardo was commissioned to create a monument in honour of Francesco Sforza.
In his notebooks are a series of plans for an equestrian monument.
There are also a large number of related anatomical studies of horses.
They include several diagrams of a standing horse with the angles and proportions annotated, anatomical studies of horses' heads, a dozen detailed drawings of hooves and numerous studies and sketches of horses rearing.
He studied the topographical anatomy of a bear in detail, making many drawings of its paws.
There is also a drawing of the muscles and tendons of the bear's hind feet.
Other drawings of particular interest include the uterus of a pregnant cow, the hindquarters of a decrepit mule and studies of the musculature of a little dog.