A neckbone was a bone found in the skeletal systems of some humanoids (such as Cardassians).
Leskit, helmsman during General Martok's first command of the IKS Rotarran, wore a necklace made of Cardassian neckbones in 2373. (DS9: "Soldiers of the Empire")
Cardassian neckbones likely formed the distinctive neck ridges in the species. Constable Odo emphasized that the neckbones were
Cardassian neckbones, implying that other species have neckbones as well.