SkullThe skull has no teeth. The sharp edges of its jaws are covered by a horny beak.
CarapaceThe domed upper half of the shell. It is built from the ribs, the backbone and plates of bone that form in the skin.
PlastronThe flat lower half of the shell. It is made of nine bones.
Cervical vertebraeThe eight vertebrae of the neck. Unlike those of the trunk, they are free to bend.
RibsBroad ribs that are part of the carapace. Each one is grown together with a costal bone.
Dorsal vertebraeThe vertebrae of the trunk, fixed under the carapace. They cannot move on one another.
Shoulder girdleThe scapula and coracoid, which carry the front leg. In a turtle they lie inside the rib cage.
HumerusThe upper bone of the front leg, from shoulder to elbow.
PelvisThe hip bones, three on each side: ilium, pubis and ischium. The ilium reaches up to the backbone.
FemurThe thigh bone, the upper bone of the hind leg.
Caudal vertebraeThe vertebrae of the tail. Like those of the neck, they are free to bend.
BridgeThe part of the shell that joins carapace and plastron. There is one on each side, between the front and hind legs.
The bones of the shell 11
NuchalThe single wide bone at the front of the carapace. It lies on the midline.
EpiplastronThe front pair of bones of the plastron. They are thought to match the collarbones of other animals.
EntoplastronThe single bone on the midline of the plastron. The first two pairs of bones enclose it.
NeuralsA row of small bones along the midline. Each is joined to a vertebra beneath it.
HyoplastronThe second pair of bones of the plastron. Each helps form the front of the bridge.
CostalsEight broad bones on each side of the neurals. Each is grown together with a rib, and they are also called pleurals.
PeripheralsThe ring of small bones around the edge of the carapace. Older books call them marginal plates.
HypoplastronThe third pair of bones of the plastron. Each helps form the rear of the bridge.
XiphiplastronThe last pair of bones of the plastron, at its rear end.
SuprapygalsOne or two bones behind the last neural. They lie between the last costals, in front of the pygal.
PygalThe last bone of the midline, on the rear edge.
How this list was compiled: Every name and detail line was checked on 2026-10-03 in at least two sources, for facts only and with nothing copied: (1) O. P. Hay, The Fossil Turtles of North America, 1908 (public domain), the chapter on the osteology of the turtles, https://archive.org/details/fossilturtlesofn00hayo; (2) T. J. Parker and W. A. Haswell, A Text-book of Zoology, volume 2, 1910 (public domain), the skeleton of the Chelonia, https://archive.org/details/textbookofzoolog02parkrich; (3) Wikipedia, Turtle shell; (4) Wikipedia, Turtle. A name that only one source gives is left out of the parts. Unofficial study material, not affiliated with any textbook, course or exam; check your own course material. Licence: own work
The drawing: Drawn for this site on 2026-10-03 from plain shapes. Own original schematic drawing; nothing traced or copied. Licence: own work
How it works
This diagram of a turtle skeleton has two views. The first shows the skeleton from the side with half the shell taken away. The second shows the bones of the carapace from above and of the plastron from below.
Read the full guide
The skeleton from the side
The carapace arches over the top and the plastron lies underneath; the bridge joins them between the legs. The trunk vertebrae and the ribs are fixed inside the carapace. The shoulder girdle and the pelvis stand inside the shell, so the leg bones start under the ribs.
The bones of the shell
The second view shows the carapace with the nuchal in front, the neurals down the midline, the costals beside them and the ring of peripherals, then the nine bones of the plastron. Tap a name for a line about that bone. Quiz me hides the names.
The horny scutes on a live turtle do not match the bones under them in number or in place.
Hyo comes before hypo: the hyoplastron is the second pair of the plastron and the hypoplastron the third.
Questions and answers
Is a turtle's shell part of its skeleton?
Yes. The carapace is built from the ribs and the backbone, grown together with plates of bone that form in the skin. The plastron is made of nine more bones. The horny scutes on the outside only cover this bone.
How many bones are in a turtle shell?
About 50 to 60. A 1908 account of a North American pond turtle counts 50 bones in its carapace and 9 in its plastron.
Do turtles have ribs?
Yes. The ribs are broad and are part of the carapace: each one is grown together with a costal bone, so the ribs cannot move.
Where are a turtle's shoulder blades?
Inside the rib cage. In other four-legged animals the shoulder blade lies outside the ribs, but a turtle's shoulder girdle and pelvis both sit inside the shell.
Is a tortoise skeleton different from a turtle skeleton?
A tortoise is a land-dwelling turtle, so this also serves as a tortoise skeleton diagram: the shell is built on the same plan and the neck has eight vertebrae. A tortoise's legs are column-like, with short toes.