Where it is
Midline of the back, from the base of the skull to the coccyx: 7 cervical, 12 thoracic, 5 lumbar, 5 fused sacral and 4 fused coccygeal vertebrae.
What it does
Supports the head and trunk, protects the spinal cord, allows bending and twisting, and absorbs shock through the intervertebral discs. Its natural curves (cervical and lumbar lordosis, thoracic kyphosis) balance the body.
Clinical relevance
- A herniated lumbar disc (most often L4–L5 or L5–S1) presses on a nerve root and causes sciatica.
- Lumbar punctures are performed below the end of the spinal cord, usually at L3–L4 or L4–L5.
- Osteoporotic vertebral compression fractures cause height loss and kyphosis.
Nursing focus
- With a suspected spinal injury, keep the spine aligned and log-roll the patient with enough staff.
- After a lumbar puncture, encourage fluids and report a headache that worsens when upright.