Spine
The spinal column (columna vertebralis) is the axial skeleton of the body, consisting of 33–34 vertebrae. It performs supporting, protective (spinal cord) and shock-absorbing functions, and also ensures mobility of the torso.
Spinal sections
| Department | Number of vertebrae | Designation | Features |
|---|---|---|---|
| Cervical | 7 | C1–C7 | Greatest mobility |
| Chest | 12 | Th1–Th12 | Joints with ribs |
| Lumbar | 5 | L1–L5 | Heaviest load |
| Sacral | 5 (fused) | S1–S5 | Forms the posterior wall of the pelvis |
| Coccygeal | 3–5 (fused) | Co1–Co5 | Tail vestige |
Structure of a typical vertebra
Each vertebra consists of:
- Body - massive front part that carries the main load
- Arch - the back part forming the spinal canal
- Processes: spinous (backward), two transverse (to the sides), four articular (up and down)
Physiological curves
The spine is not straight - it has 4 bends:
- Cervical lordosis - forward convexity
- Thoracic kyphosis - convexity backwards
- Lumbar lordosis - forward convexity
- Sacral kyphosis - convexity backwards
The S-shape increases the resistance of the spine to axial loads by 10 times compared to a straight column. Stability formula: R = N² + 1, where N is the number of bends. With 4 bends: 4² + 1 = 17 times stability.
Ligamentous apparatus
- Anterior longitudinal ligament - runs along the anterior surface of the vertebral bodies from the back of the head to the sacrum
- Posterior longitudinal ligament - along the posterior surface of the bodies (inside the spinal canal)
- Yellow ligaments - connect the arches of adjacent vertebrae, contain elastin
- Interspinous and supraspinous - between the spinous processes
Special vertebrae
Atlas (C1) - has no body, represents a ring with two arcs. Provides nodding movements of the head.
Axis (C2) - has an odontoid process (dens), around which the atlas rotates along with the skull. This provides head rotation 90° in each direction.
Understanding the anatomy of the spine is necessary for vertebrologists, neurologists and neurosurgeons to diagnose and treat disc herniations, stenoses and deformities.
All parts of the spine - from the atlas to the coccyx - can be studied in the free 3D atlas Humio. Rotate the model, scale and examine each vertebra.