A clavicle or collar bone is a flat bone that makes up part of the shoulder.
In Klingon mating rituals, it is seen as a blessing on a marriage to have a clavicle fractured during a Klingon wedding. (VOY: "Blood Fever")
In 2372, Drex and a few Klingons fractured Elim Garak's clavicle after attacking him in his shop. (DS9: "The Way of the Warrior")
Later that year, a crew member on the USS Voyager fractured her clavicle after the ship was severely damaged by proton bursts. (VOY: "Deadlock")