Vertebral Column and Pelvis Explorer
Turn the whole spine in 3D, atlas to sacrum, with both hip bones. The cervical, thoracic and lumbar curves are visible from the side.
Visualiser
Vertebral column and pelvis, 27 bones
Checking this device for a stored copy.
Start here
- Turn to Left and look along the column The curves are real and smaller than textbooks draw them. The fourth lumbar sits about 60 mm in front of the seventh thoracic.
- Select one vertebra from each colour band in turn The bodies get steadily larger going down, because each one carries everything above it. Only the thoracic ones have rib facets.
- Hide the Sacrum and pelvis group Leaves the movable column on its own, which is the part that actually bends.
Bone only. No coccyx, because BodyParts3D publishes the coccygeus muscles and no coccyx bone. No intervertebral discs, which are what actually transmit load between these bones. The dataset publishes them, but this model leaves them out, so the empty gaps between the vertebral bodies are where they belong; the full skeleton explorer shows them in place. No ligaments and no spinal cord.
- 27 bones
- 267k triangles
- 1450 KB, on request
- 0.00558 mm worst error per axis
- 7 cervical
- 12 thoracic
- 5 lumbar
- 3 sacrum and pelvis
24 movable vertebrae, the sacrum and both hip bones, which is 27. A vertebral column is usually described as 33 vertebrae, of which the lowest nine are fused into the sacrum and coccyx. There is no coccyx here because BodyParts3D does not publish one, so the column ends at the sacrum.
Where this comes from
Segmented from imaging of one adult male body, not drawn by an artist, so the shapes are measurements. Two consequences worth knowing: it is one person’s anatomy rather than an average, and faint stepping on some surfaces is the resolution of the original scan rather than a rendering fault.
Meshes from BodyParts3D, © The Database Center for Life Science, under Creative Commons Attribution 4.0 International. Names and identifiers are the dataset’s own: Foundational Model of Anatomy identifiers and English labels, as its parts list gives them. Converted meshes are shared under the same licence.
Changes made: Meshes were converted from binary STL to an indexed mesh with 16-bit quantised vertex positions, and surface normals were recomputed from the geometry. No vertex was moved other than by that quantisation, whose worst-case error on any one coordinate is reported on the page.
Latin terms for 5 of the 27 structures come from English Wikipedia anatomy infoboxes, under Creative Commons Attribution-ShareAlike 4.0, joined by Wikidata property P1402, Foundational Model of Anatomy identifier. Only a term a source states for that structure is used, never one constructed from a family name, which is why the rest carry no Latin rather than a guess.
All 27 bones
Every structure the model contains, group by group. Each name opens the viewer with that structure selected, so a link can point at one bone rather than at the whole region.
Cervical 7
- atlas atlas, vertebra cervicalis I
- axis axis, vertebra cervicalis II
- third cervical vertebra
- fourth cervical vertebra
- fifth cervical vertebra
- sixth cervical vertebra
- seventh cervical vertebra
Thoracic 12
Lumbar 5
Sacrum and pelvis 3
- sacrum os sacrum
- right hip bone os coxae, os innominatum
- left hip bone os coxae, os innominatum
Citing this tool
Last updated . Add the date you accessed it as well, which a citation of a page that can change asks for. If a specific view matters, cite the page address as it stands in your browser instead: it records what is selected and shown.
The curves are measurable, and modest
Measured on this specimen, the fourth lumbar vertebra sits about 60 mm in front of the seventh thoracic. That is close to the largest front-to-back displacement in the whole column and the reason the curves read from the side at all. Most diagrams draw a far more dramatic S than the bones support.
One plan, three jobs
- Cervical
- Small bodies, wide canals, and the two at the top so specialised that the atlas has no body at all and the axis carries a peg, the dens, that the atlas pivots on.
- Thoracic
- The only ones with facets for ribs, which is what makes them thoracic rather than a size class.
- Lumbar
- The bulkiest bodies, and short, thick, hatchet-shaped spinous processes. These carry the most.
The sacrum below them is five vertebrae fused into one wedge, and the four transverse ridges across its front, with an anterior sacral foramen at each end of every ridge, still mark where they were separate.
Common questions
How many vertebrae are there, and why do counts differ?
This model carries the movable ones, from the atlas down to the fifth lumbar, plus the sacrum as a single fused wedge. The usual figure quoted for a whole column is higher because it counts the sacrum as five and adds three to five fused coccygeal vertebrae, none of which is in this dataset: BodyParts3D publishes the coccygeus muscles but no coccyx bone. So the honest answer is that the number depends on whether you count fused segments individually, and any source giving one figure without saying which it means is being imprecise.
Can you actually see the spinal curves in this model?
Yes, and they are smaller than textbook drawings suggest, which is worth recalibrating against. Measured on this specimen the fourth lumbar vertebra sits about 60 millimetres in front of the seventh thoracic, which is close to the largest front-to-back displacement anywhere in the column and what makes the thoracic and lumbar curves visible from the side at all. The exaggerated S in most diagrams leads people to expect something far more dramatic. Use the Left or Right view to see it side on.
How do cervical, thoracic and lumbar vertebrae differ?
By how much load they carry and what attaches to them, and the model shows both. Turn to the side and the bodies get visibly larger going down, because each one supports everything above it. The thoracic ones carry facets where the ribs hinge, which the others do not. The lumbar ones are the bulkiest, with short, thick, hatchet-shaped spinous processes. Selecting one from each group in turn is a faster way to learn the differences than a table, because the differences are shapes.
Why is the pelvis in a spine model?
Partly because the sacrum is a pelvic bone as much as a spinal one, so cropping between them would cut the region at a joint rather than at a bone. And partly for a reason worth being open about: every vertebra sits on the midline, so no pair of them can tell left from right, and the view buttons marked Left and Right would have been a coin flip. The two hip bones fix it. A spine seen from either side looks much the same, so nothing else in the model would have revealed a mistake.