What is the Vertebral Column?
The vertebral column, or spine, is the flexible bony axis that runs from the skull to the pelvis. It is built from stacked vertebrae separated by cushioning discs, and it both supports the body's weight and protects the spinal cord.
The vertebral column is a segmented chain of 26 bones (33 before some fuse) in an adult, divided into cervical, thoracic, lumbar, sacral and coccygeal regions, that supports the trunk and shields the spinal cord.
- 1↓Cervical (C1–C7)7 vertebrae in the neck; C1 (atlas) and C2 (axis) allow head rotation.
- 2↓Thoracic (T1–T12)12 vertebrae, each articulating with a pair of ribs.
- 3↓Lumbar (L1–L5)5 large vertebrae bearing most of the body's weight.
- 4↓Sacrum5 fused vertebrae forming the back of the pelvis.
- 5Coccyx3–5 small fused vertebrae, the tailbone.
Step-by-step worked examples
How many vertebrae does an adult have after fusion, and how is that number reached?
Start with 33 vertebrae in a child: 7 cervical + 12 thoracic + 5 lumbar + 5 sacral + 4 coccygeal The 5 sacral vertebrae fuse into 1 sacrum, and the 4 coccygeal vertebrae fuse into 1 coccyx 7 + 12 + 5 + 1 + 1 = 26 bones in the adult spine
A patient has damage at vertebral level T6. Which region and approximate rib pair is involved?
T = thoracic region, so this is the 6th thoracic vertebra Each thoracic vertebra articulates with a corresponding rib pair T6 corresponds roughly to the 6th rib pair, near the middle of the rib cage
Why can C1 and C2 allow the head to rotate about 80° while other vertebrae cannot?
C1 (atlas) has no vertebral body and cradles the skull like a ring C2 (axis) has a bony peg (the dens) that the atlas pivots around This atlantoaxial joint is a pivot joint, unlike the limited gliding joints of C3–C7
Flashcards
Quick quiz
Q1.How many vertebrae are in the adult vertebral column?
Q2.Which region of the vertebral column has 12 vertebrae?
Q3.What structure cushions adjacent vertebrae?
Q4.Which vertebra is known as the 'axis'?
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Common mistakes
Thinking the spine has exactly 33 separate movable bones in adults. — Correct: Only 26 bones move independently in adults — the sacral and coccygeal vertebrae fuse into the sacrum and coccyx.
Believing the spinal cord runs the full length of the vertebral column. — Correct: The spinal cord itself typically ends around L1–L2; below that, spinal nerves form the cauda equina.
Assuming all vertebrae look the same. — Correct: Cervical, thoracic and lumbar vertebrae differ in size and shape to match their function (mobility vs. load-bearing).
Confusing the atlas and axis. — Correct: C1 (atlas) supports the skull like a ring; C2 (axis) provides the pivot (dens) for rotation.
FAQ
What is the vertebral column?
It's the spine — a chain of 26 bones (in adults) that supports the trunk, protects the spinal cord and allows flexible movement.
How is the vertebral column divided into regions?
Into five regions: cervical (neck), thoracic (upper back), lumbar (lower back), sacral and coccygeal.
How many bones are in the vertebral column?
26 in an adult: 7 cervical, 12 thoracic, 5 lumbar, 1 sacrum, and 1 coccyx (the last two are each made of fused vertebrae).
What is the function of the intervertebral discs?
They cushion each pair of vertebrae, absorbing shock and permitting slight bending and twisting of the spine.