Castrati, boys castrated before the onset of puberty to preserve their high-pitched voices, played heroic male leads in Italian opera from the mid-17th to late 18th centuries.
Farinelli, born Carlo Broschi in 1705, was the most famous castrato, in a stage career lasting from 1720 to 1737.
Carlo Vitale of the Farinelli Study Centre in Bologna said they had recovered the bodies of the singer and his great-niece, who moved his body from a first grave destroyed in the Napoleonic wars.
His final resting place in Bologna's Certosa cemetery was discovered only recently.
His remains were to be taken to Bologna University for study by a team of scientists including an acoustics expert who wantes to find remains of the vocal cords and larynx to discover what gave castrati their range and power.
Nicholas Clapton, a British expert on castrati, said: "This is the only skeleton of them we have.
"We want to know if they were like the cartoons at the time depicted them, tall and gangly, or with women's breasts and large buttocks, or like the grand gentleman in Farinelli's official portraits."
"Pavarotti on helium"
Clapton, who is a singing professor at the Royal Academy of Music in London and curator of an exhibition on Handel's use of the castrati, said the removal of boy choristers' testicles kept their vocal cords small but the hormonal changes meant that their bodies kept growing well into adulthood.
"That gave them huge lung capacity but with a very sweet voice," he said.
It could also mean that castrati grew abnormally tall or fat and could sprout breasts, though surviving official portraits of Farinelli depict him as having a normal build.
Castrati also had their critics, who thought that their voices were ghastly and their mutilation was barbaric.
The Roman Catholic church used castrati in choirs and in the Vatican's Sistine Chapel until as recently as 1903, Clapton said.
The last surviving castrato, Alessandro Moreschi, lived long enough to make recordings in 1902 and 1904, though on the dated gramophone records his voice sound like what Clapton described as "Pavarotti on helium".