Cartilage was part of the body of animals.
Permians appeared to be animated skeletons of theropod dinosaurs, their bodies composed of bone and cartilage and held together by a bioelectric field generated by the brain. (AUDIO: The Land of the Dead)
Brother Myina was known as Broken Wing for the broken cartilage in his left wing. (PROSE: The Krillitane Storm)
Nano-recorders were implanted in the palms of the users' hands, fusing with the cartilage there. (TV: Day of the Moon)