Sarah "Crazy Sally" Mapp (baptised 1706 – 1737) was an English lay bonesetter, who gained fame both by performing impressive bone-setting acts in Epsom and London, and by being a woman in a male-dominated profession.

[4] John Wallin was a bone-setter as well, and when he was unable to conduct bone setting practices, Mapp carried on and dealt with the cases, often even better than her father.

Lavinia Fenton played Polly Peachum in The Beggar's Opera in 1728 and later married Charles Powlett, 3rd Duke of Bolton.

Some of her most noteworthy cases are recorded in James Caulfied's Portraits, Memoirs, and Characters of Remarkable Persons where he recorded an account from October 21, 1736, "On Monday, Mrs. Mapp performed two extraordinary cures; one on a young lady of the Temple, who had several bones out from the knees to her toes, which she put in their proper places: and the other on a butcher, whose knee-pans were so misplaced that he walked with his knees knocking one against another.

Yesterday she performed several other surprising cures; and about one set out for Epsom, and carried with her several crutches, which she calls trophies of honour.

"[5] At one point, some surgeons tried to fool Mapp and show that she was not skilled by sending her a healthy patient who claimed he had a damaged wrist.

A song about Mapp appeared in a contemporary play at Lincoln's Inn Fields, The Husband's Relief, comparing her favorably to highly-paid London surgeons.

In 1736, the established medical community started to try to eliminate the "quacks" operating in London, so Mapp moved to Pall Mall.

[4] Hogarth's print was coupled with Sir Percivall Pott's criticism of Mapp when he called her "an immoral drunken female savage".

[1] Sarah Mapp was only alive for thirty years, but she is still well recorded in history because of her character and the fact that she was a very successful female in what was typically considered a male field.

[12][13] Samuel Homola has noted that "In the days of Sally Mapp, the treatment appeared to be quite successful in a great many conditions because of the unrecognized effects of suggestive therapy.