The central part of the turtles bone structure is the spine, probably the most specialized vertebral structure among vertebrates.
It has eight cervical, ten trunk vertebrae and 25 to 30 caudal vertebrae. The function of the vertebrae is to protect the spinal cord, but in turtles, since it is covered by a shell, the dorsal ( upper ) vertebrae have considerabely degenerated. The trunk vertebrae are attached to the carapace and the pelvis is fused to the carapace and plastron.
The large number of caudal vertebrae in the tail are supported by very well developed muscles and enable the movement throughout its full length.

The limb gridles are housed within the rib cage resting against the carapace and give a solid base to the sockets, enabling them to withstand strong upward pressure.

The limb bones are short, massive and very strong. Those closest to the body are made of one bone, called humerus for forelimbs and femur for hind limbs. The two more distant parallel bones are called radius and ulna for forelimbs and tibia and fibula for hind limbs.

The foot structure varies greatly among turtles, and most turtles have pentadactyl limbs - typically five claw - bearing digits in the forefoot and four claw - bearing digits with one reduced clawless digit in the hind foot.

The head of almost all the turtle species ( except the sea turtles and few other land species ) is retractable. The roof of the skull is sculpted in such a way that the jaw muscles bulge out when the jaw is rapidly closed as the head is retracted into the shell.
Also the alveolar - biting surfaces of the jaw - vary greately according to a turtle's diet. For example, the jaws of the preditory turtles like the common snapping turtle , are exeedingly sharp and hooked, for the purpose of catching and slicing prey.
( compare the common snapping turtle skull with the skull of the alligator snapping turtle )

The hyoid bones are bones not connected with the rest of the skelton. They are made up of a central body and two pairs of horns embedded in the flesh of the tongue and the neck. The hyoid body has a groove in which the windpipe ( tradhea ) lies.