I want to talk about something I hate but it seems interesting to most people. I do not feel very comfortable but, here goes ...

No, the legend does not tell ... Because serious studies were realized and something real seems to have been established in fact. I say seems because it is difficult to separate the wheat from the chaff, as in everything that refers to the Inca Empire. They blend the various cultures and civilizations, which formed the basis for the formation of the Inca Empire (Mochica, Chimu, Tiahuanaco, Huari, Chavin) but, in fact and in truth, only influenced their culture - their way of fighting, of govern, their rules, everything, in short, was organized and implemented in very few years. We are speaking here of thousands of years of pre-Inca civilizations against a hundred and a few years of the Inca Empire. However, who am I to contradict those who engage in studies, and further studies, scientific studies to determine what was and what was not.
Then, half legend, half reality, as it is said currently ... "breaking the fabric of reality", here we go ...
Studies tell that...

When an Inca was sick, called the qampy camayoq-(or hampicamayoc), literally a "responsible for the drugs" and he had a duty to care for the health of the Inca and his family. Valdivia (1) (1986) says concerning this: "was the real doctor in the strict sense of the word, and pursued the medicine exclusively for the service of the Inca and the nobility."

However, in spite of people in the Inca and his family, which would put him in a away position from ordinary people, we know, through those medical studies that the qampy camayoq acted effectively in war, for example, where applied a very advanced Medicine and with excellent results, although, of course, could not save all who needed their precious help.

Surgery, anesthetics and other surgical practices were advanced among the Incas, as well as in pre-Inca cultures that preceded them - they performed the most delicate operations of the skull, trepanning the heads of injured warriors by the impact of battle ax and removing pieces of bone that pushed the brain, causing paralysis.

Numerous skulls found in the tombs show regeneration of bone tissue, revealing that a surgical operation performed, there, was successful. Similarly, skulls were discovered, which had suffered surgical interventions, in tombs of the previous cultures of about two thousand years.

It is now evident that, thanks to studies of surgeons in Peru, Francisco Grana and Esteban Rocca, the progress in this area of medicine in the Inca period can be, properly, proved - with the same tools and employing the same surgery techniques of the Incas (with aside from general anesthesia), Grana and Rocca made ​​a trepanning in a living patient. Similarly, they applied a tourniquet inca ( applied around the head), proving the effectiveness of their surgical methods.
At the height of the Empire, as at the time of Tupac Yupanqui and Huayna Qhapaq, for example,there was two hundred thousand warriors in one army; ten thousand members just in the imperial guard (elite troops). Reportedly, the Incas were able to mobilize millions of soldiers (Pachacutec (2) had four and a half million soldiers in his campaigns and, Tupac Yupanqui, six millions).
One of offensive weapons the most common was the macana (Chaska Chuqui Quechua, or spear with star-tip ), an instrument whose "scathing end" was round or star-shaped and made ​​of stone or bronze - were the most common weapons of the Inca army and were made of gold or silver, according to the graduation of the soldier. The best place to strike the blow was the head, being abundant the brain lesions acquired in battle. Realizing the connection between the injury caused by a macana and the pressure in the brain, the qampy camayoq developed the technique of trephination.
More than 10 000 operated skulls were found inside tombs throughout Peru, and many of them, surgical instruments, like obsidian knives (type of natural glass, black or dark colored, produced by volcanoes when lava cools quickly) - the obsidian blades can have a cutting edge so fine as that of steel surgical scalpels of high quality, with wooden handles for trephination. Also tumis were found (ceremonial knives), that were used to cut the scalp. As part of the arsenal surgical, slitters (scopes) of bronze, tweezers made of copper and suture needles. It was with these tools that the doctors Grana and Rocca performed the trepanation in a living patient.
In the Inca Empire, neurosurgery was advanced and sophisticated. It was evident the delicacy that surgeons had to operate, as they preserved important grooves and convolutions of the brain. There were few infections, because they used antiseptic herbs. The used anesthesia  is not known but is likely that they have used coca. Healing and recovery were obtained in 70% of cases.
There's no agreement to determine which plant would have been used to produce general anesthesia required to prepare a patient with a fractured skull, to receive assistance from a qampy camayoq therefore I will not attempt to describe any of the possible plants. However, due to be the most sacred leaf of the Incas, coca, whose botanical name is Erythroxylum coca, grown in the warm yungas and lower parts of the eastern Andes, may indeed have been chosen, because is a plant in whose leaves, there is an alkaloid known as mehtyl-benzyl-ecogine. There was a time that was used as a local anesthetic and also in 1900, was considered a wonderful tonic for the nerves. The wine of coca enjoyed much appreciation, Sigmund Freud was an inveterate consumer.
From glossy leaves, which have some resemblance to those of tea, these leaves are cut four times in fourteen months, and placed carefully to dry in the sun, and later transferred to the shade in order to retain the green color. However, this would be mere speculation, despite the sacred role of coca in the Inca Empire, I think would be very difficult to prove this.
The pre-Columbian medicine was linked to religion (some diseases were attributed to the gods, as well as its treatment), to the magic (some believed that diseases were caused by witches) and to the science (they knew the healing properties of plants and some minerals ). It was also practiced by healers, who belonged to the caste of priests. Parents teach the profession to their children and they inherited the job. The doctor enjoyed high regard throughout the pre-Columbian society.

The Incas made ​​many pharmacological discoveries: they used quinine to treat malaria. Coca leaves were used, generally as an analgesic and to
alleviate hunger, although the messengers Chasqui (men who rushed to carry messages throughout the Inca empire) used them for extra energy.
Felipe Guaman Poma de Ayala, better known as Huaman Poma, who was born in 1550, wrote a manuscript, with complete information on the practice of medicine during the Inca civilization, the manuscript was kept in the Royal Library of Denmark since 1660, only coming to the public in 1908 when he was discovered by German scholar Richard Pietschmann.

According to the manuscript, the Incas believed that all diseases were caused by the action of supernatural forces. Moreover, the lies, sins against the gods or breaking the Incas  laws are sufficient reasons to be sick. The remedies were combinations of herbs and minerals, always accompanied with prayers and spells.
Physicians Incas were able to successfully treat diseases of the immune system, increasing the production of white blood cells or leukocytes, which naturally stoped the advance of some diseases. They knew how to treat urinary diseases and respiratory disorders such as coughs and bronchitis; how to restore the proper functioning of the gastrointestinal system and sexual performance problems, among others.
The Inca Medicine had three doctor types: the first type called Watukk - his job was to discover the origin of the disease, through an interpretive process of the daily life of the sick person; Watukk tracked the global somatic, the emotional and the phase of the pathology of the patient - he was entirely responsible for the correct diagnosis.
Hanpeq is the second kind of doctor: he was responsible for applying his medical knowledge about the disease, mixing and linking the properties of herbs and minerals to cure the patient, placing special attention on the correct application of the remedy and post-treatment. The Hanpeq is what we today call the Shaman, who is a religious, mystic and doctor of natural medicine.
The last type of doctor is the Paqo: his work was strictly focused on the treatment of the soul, the Incas believed that the soul was located in the heart. The paqo was responsible for synchronizing the health of the spirit with the body, his main purpose was to prevent and treat adverse reactions of drugs in the body to affect as little as possible, the living conditions of the patient.
The Inca medicine was so complex that classified and treated the sadness, melancholy, mental illness, severe afflictions of the behavior, anger, cowardice, regret, anxiety, sadness, pathological fear, dementia, severe psychotic disorders such as madness, insanity, idiocy and hysteria, among others.

The medical school Inca could last from three to five years depending on the skill of the student. It was a rigorous education in studying the properties of herbs and minerals, how to use them, the quantities of drugs, disease diagnosis. They taught students how to recognize the known diseases and how they should be treated. After the student complete the medical course, he had to pratice many years before being considered a doctor.

The doctors were in constant search for new herbs and minerals, looking for new solutions and improving old ones. The search for answers is the reason of its great development. The healing power of medicine Inca was absolutely extraordinary. Besides its religious side and magical spells, which were part of treatment, the doctors helped the patient to believe he was healed, a fact that releases endorphins into the bloodstream, helping the self-healing of the body.

According to Poma, medicine Inca had remarkable 80 to 90 percent survival rate in surgical procedures of the skull. Incredible, considering the materials and medical knowledge at the time, the wounds of sewing procedings were absolutely perfect, with few cases of infection. We have very few manuscripts that describe how the doctors worked; it is sad to realize that most of this knowledge has been lost in the past.

1) VALDIVIA, P.O. (1986). Hampicamayoc. Medicina folklórica y su subestrato aborigen en el Perú. UNMSM. Lima

(2) Garcilaso de La Vega - Comentarios Reales de los Incas.