A hand was a body part.
To demonstrate the cause of the stalemate of the Dalek-Movellan War, the Fourth Doctor and Romana played a game involving hand shapes forming "stone", "paper" and "scissors". (TV: Destiny of the Daleks)
The Abzorbaloff had hands with three clawed fingers, which exposed him as alien to Ursula Blake and Elton Pope when he attempted to hide behind a copy of The Daily Telegraph newspaper. Ursula was absorbed into the Abzorbaloff's body when his hand grabbed her arm. (TV: Love & Monsters)
Immediately following his regeneration, the Tenth Doctor made sure to check that he still had, among other things, two hands, noting a "slight weakness" in the dorsal tubercle of his right. (TV: Children in Need Special) This hand was cut off during a sword fight against the Sycorax leader. (TV: The Christmas Invasion) Jack Harkness later retrieved the hand and returned it to the Doctor in a jar in the year 100 trillion. (TV: Utopia) Later, when forced to regenerate, he healed himself and channelled the excess energy into the hand, a bio-matching receptacle. (TV: Journey's End) After the Daleks captured the TARDIS, they attempted to destroy it. Still inside during this apparent destruction, Donna Noble touched the energised hand's container. The regenerative energies within the hand combined with Donna's human DNA. The force of the reaction shattered the container, allowing the creation of the "Meta-Crisis Tenth Doctor". (TV: Journey's End)
The Thirteenth Doctor's hands were noticeably smaller than her predecessor, causing the ring that he had worn to be released and fall to the TARDIS control room floor upon his regeneration. (TV: Twice Upon a Time)
When the Thirteenth Doctor visited Villa Diodati in June 1816, a bony hand of a human skeleton possessed by Lord Byron mysteriously came to life and started attacking people. (TV: The Haunting of Villa Diodati)
The Doctor had a habit of holding the hands of the people he was leading to safety. (TV: The Night of the Doctor, Rose, The Witch's Familiar) He was protective of this habit, the Eleventh Doctor protesting when Clara Oswin Oswald grabbed his hand to lead him to safety. (TV: The Snowmen)