33. VERTEBRAL COLUMN

The human spinal column is a flexible, S-shaped structure composed of 33 vertebrae divided into five regions—cervical (7), thoracic (12), lumbar (5), sacrum (5 fused), and coccyx (4 fused). It protects the spinal cord, supports the head and upper body, and allows movement. Intervertebral discs act as shock absorbers, while ligaments and muscles provide stability. 

Key Regions of the Spinal Column

• Cervical (Neck): Seven vertebrae (C1-C7) supporting the head, with C1 (atlas) and C2 (axis) allowing for rotation.

• Thoracic

  (Mid-Back):

  Twelve vertebrae (T1-T12) connected to the ribs, allowing for limited movement to protect internal organs

  .

Anatomical Structure and Function

• Vertebrae Anatomy: Each vertebra consists of a body for weight-bearing, a vertebral arch for spinal cord protection, and processes for muscle attachment.
• Spinal Curves: The spine has natural curves (lordotic in the neck/low back, kyphotic in the mid-back) that distribute weight and absorb shock.
• Intervertebral Discs: Gel-filled, fibrocartilage pads between vertebrae that provide cushion and prevent rubbing.
• Spinal Cord & Nerves: The spinal cord runs through the spinal canal, with 31 pairs of nerves exiting to facilitate communication between the brain and body.