Vertebral column

Anatomy of the Human Skeletal System

1. Overview of Major Bones

  • Cranium: Protects the brain, comprises multiple bones.

  • Facial Bones: Form the structure of the face.

  • Pectoral Girdle: Makes up the shoulder region, includes the clavicle and scapula.

  • Thoracic Cage: Consists of ribs and sternum, protects thoracic organs.

  • Upper Limb: Includes humerus, radius, ulna, carpals, metacarpals, and phalanges.

  • Vertebral Column: Made up of vertebrae categorized into cervical, thoracic, lumbar, sacral, and coccygeal regions.

  • Lower Limb: Comprises femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges.

2. Regions of the Vertebral Column

  • Cervical Vertebrae (C1-C7):

    • 7 vertebrae, C1 (Atlas) supports the skull.

    • C2 (Axis) allows rotation of the head.

  • Thoracic Vertebrae (T1-T12):

    • 12 vertebrae, each articulating with ribs.

  • Lumbar Vertebrae (L1-L5):

    • 5 vertebrae, supports the lower back.

  • Sacral Vertebrae:

    • 5 fused vertebrae forming the sacrum.

  • Coccygeal Vertebrae:

    • 3-4 fused vertebrae forming the coccyx.

3. Curvatures of the Vertebral Column

  • Cervical Curvature: Secondary curve (concave).

  • Thoracic Curvature: Primary curve (convex).

  • Lumbar Curvature: Secondary curve (concave).

  • Sacral Curvature: Primary curve (convex).

4. Structure of Vertebrae

  • Parts of a Typical Vertebra:

    • Body (Centrum): Main weight-bearing portion.

    • Vertebral Arch: Contains pedicles, laminae.

    • Spinous Process: Projects posteriorly; muscle attachment.

    • Transverse Processes: Lateral projections; muscle attachment.

    • Articular Facets: Allow articulation with adjacent vertebrae.

5. Specific Vertebrae

5.1 Atlas (C1)

  • Supports the skull.

  • Lacks a body; has the anterior and posterior arch.

5.2 Axis (C2)

  • Features the dens (odontoid process) for rotation.

6. Joints and Ligaments

  • Intervertebral Discs: Fibrocartilaginous pads between vertebrae, contain nucleus pulposus and anulus fibrosus.

  • Zygapophysial Joints: Facet joints between articular processes of adjacent vertebrae.

  • Ligaments:

    • Anterior and Posterior Longitudinal Ligaments: Reinforce vertebral column; limit flexion and extension.

    • Ligamenta Flava: Connect laminae of adjacent vertebrae.

    • Supraspinous and Interspinous Ligaments: Connect spinous processes.

7. Muscles of the Back

7.1 Extrinsic Back Muscles

  • Superficial Group: Trapezius, Latissimus dorsi, Rhomboids.

  • Intermediate Group: Serratus posterior superior/inferior.

7.2 Intrinsic Back Muscles

  • Erector Spinae Group: Iliocostalis, Longissimus, Spinalis.

  • Deep Group: Multifidus, Rotatores and Intertransversarii.

8. Blood Supply

  • Vertebral Arteries: Supply blood to the cervical spine.

  • Internal and External Venous Plexuses: Drains blood from the spine.

9. Pathological Conditions

  • Herniated Discs: Displacement of the nucleus pulposus.

  • Spina Bifida: Congenital defect in the closure of the neural tube.

  • Fractures: Various types including crush fractures and spondylolisthesis.

10. Abnormal Curvatures of the Spine

  • Scoliosis: Lateral deviation of the spine.

  • Kyphosis: Excessive thoracic curvature.

  • Lordosis: Excessive lumbar curvature.