Region · Trunk
Bones of the spine: cervical, thoracic and lumbar vertebrae and sacrum
The spine, or vertebral column, has 7 cervical, 12 thoracic and 5 lumbar vertebrae above the sacrum and coccyx. Learn how each region differs and what the spine does.
The adult spine, or vertebral column, is usually made of 26 bones: 24 separate vertebrae (7 cervical, 12 thoracic and 5 lumbar), the sacrum and the coccyx. The sacrum forms from five vertebrae that fuse, and the coccyx from three to five small ones, so the column starts out with about 33 vertebrae.
At a glance
| Bone | Muscles that originate here | Muscles that insert here |
|---|---|---|
| Atlas (C1 vertebra) | – | – |
| Axis (C2 vertebra) | – | – |
| Vertebra C3 | Levator scapulae | – |
| Vertebra C4 | Levator scapulae | – |
| Vertebra C5 | – | – |
| Vertebra C6 | – | – |
| Vertebra C7 | Rhomboid minor | – |
| Vertebra T1 | Rhomboid minor | – |
| Vertebra T2 | – | – |
| Vertebra T3 | – | – |
| Vertebra T4 | – | – |
| Vertebra T5 | – | – |
| Vertebra T6 | – | – |
| Vertebra T7 | – | – |
| Vertebra T8 | – | – |
| Vertebra T9 | – | – |
| Vertebra T10 | – | – |
| Vertebra T11 | – | – |
| Vertebra T12 | – | – |
| Vertebra L1 | – | – |
| Vertebra L2 | – | – |
| Vertebra L3 | – | – |
| Vertebra L4 | – | – |
| Vertebra L5 | – | – |
| Sacrum | Gluteus maximus, Iliocostalis, Latissimus dorsi, Longissimus, Piriformis | – |
From the anatomical data behind Anatomy Atlas 3D (Z-Anatomy, CC BY-SA 4.0, reviewed). Names link to the detailed page when there is one.
How they are organized
This page covers 25 bones, from the atlas at the top to the sacrum. The coccyx, the small tailbone below the sacrum, completes the column.
A typical vertebra
Most vertebrae share the same plan:
- A body in front, the weight-bearing part.
- A vertebral arch behind it, made of two pedicles and two laminae, which encloses the vertebral foramen. Stacked together, the foramina form the vertebral canal that protects the spinal cord.
- Seven processes: one spinous process pointing back (the bumps you feel down the middle of the back), two transverse processes pointing to the sides, and four articular processes that link each vertebra with the one above and below.
Between the bodies, intervertebral discs of fibrocartilage act as cushions. Each has a tough outer ring, the annulus fibrosus, and a soft core, the nucleus pulposus. There is no disc between the skull and the atlas, nor between the atlas and the axis.
Cervical vertebrae (C1 to C7)
The neck vertebrae are the smallest. Each has a hole in each transverse process, the transverse foramen, which in the upper vertebrae carries the vertebral artery toward the brain. The spinous processes of C3 to C6 are often split in two at the tip.
- The atlas (C1) has no body and no spinous process. It is a ring that carries the skull, which rocks on it when you nod "yes".
- The axis (C2) has a peg, the dens, that rises into the ring of the atlas. The atlas turns around it when you shake your head "no".
- C7 has a long spinous process, the vertebra prominens, usually the first bump you can feel at the base of the neck.
Thoracic vertebrae (T1 to T12)
The twelve thoracic vertebrae carry the ribs. They have costal facets on their bodies and, in most, on their transverse processes, where the ribs articulate. Their spinous processes are long and slope steeply downwards, overlapping like roof tiles. See the rib cage for how ribs and vertebrae fit together.
Lumbar vertebrae (L1 to L5)
The five lumbar vertebrae carry the most weight and have the largest, kidney-shaped bodies. Their spinous processes are short, thick and horizontal, and they have no rib facets and no transverse foramina.
Sacrum
The sacrum is a triangular bone made of five fused vertebrae. It wedges between the two hip bones at the sacroiliac joints and passes the weight of the trunk to the pelvis and the legs.
Variation
The count is not the same in everyone. Some people have a sixth lumbar-type vertebra, or a fifth lumbar vertebra partly fused with the sacrum, and the number of coccygeal pieces varies.
What they do together
The spine has three jobs: it supports the head and trunk, it protects the spinal cord, and it moves, bending forward, back and to the sides and twisting.
Seen from the side, the adult spine has four curves. The cervical and lumbar curves bulge forward (lordosis). The thoracic and sacral curves bulge backward (kyphosis). The thoracic and sacral curves are present before birth; the cervical curve develops as a baby starts to hold up its head, and the lumbar curve as the child begins to stand and walk. The curves make the column work like a spring and keep the head balanced over the pelvis.
The spine also anchors muscles, from the deep back muscles that hold you upright to the trapezius and the latissimus dorsi.
How to learn them
- Count by meals: breakfast at 7, lunch at 12, dinner at 5, for 7 cervical, 12 thoracic and 5 lumbar vertebrae.
- Spot the region by one feature. Transverse foramina mean cervical. Rib facets mean thoracic. A big body with a short, square spinous process means lumbar.
- Learn C1 and C2 as a pair. The atlas is the ring, the axis the pivot.
- Count from C7. On yourself or a partner, find the vertebra prominens at the base of the neck and count down.
Practical exams often hand you a single vertebra and ask which region it comes from, so practice recognizing each type from different angles. In the app, hide the muscle layers to see the bare spine, isolate one vertebra and rotate it, compare a cervical, a thoracic and a lumbar vertebra side by side, and use a sagittal cross section to see the vertebral canal and the curves.
Frequently asked questions
How many vertebrae are in the spine?
Most adults have 24 separate vertebrae (7 cervical, 12 thoracic, 5 lumbar), plus the sacrum and the coccyx, which are fused vertebrae.
What is the difference between the atlas and the axis?
The atlas (C1) is a ring with no body that carries the skull. The axis (C2) has a peg, the dens, around which the atlas turns.
Which vertebrae attach to the ribs?
The twelve thoracic vertebrae, T1 to T12.
Why does the spine have curves?
The forward and backward curves act like a spring, absorbing shock and keeping the head balanced over the pelvis when you stand.