Understanding the Axial Skeleton

Sep 27, 2024

Anatomy and Physiology 1: Chapter 7 - The Axial Skeleton

Overview

  • Axial Skeleton: Focus on bones that make up the axial skeleton, distinct from the appendicular skeleton.
  • Purpose: Introduction to axial skeleton components and differences from appendicular skeleton.
  • Lab Work: Detailed study of individual bones in lab sessions.

Axial Skeleton Components

  • Location: Bones of the head and trunk, forming the longitudinal axis of the body.
  • Includes: Skull, neck, trunk (ribs and vertebrae), sacrum, coccyx, hyoid bone, and ear bones.
  • Total Bones: 80 bones.

Functions

  • Support & Protection: Supports and protects organs in body cavities.
  • Muscle Attachment: Stabilizes head, neck, trunk, and assists in breathing.
  • Stabilization: Stabilizes parts of the appendicular skeleton.

Skull

  • Components: 22 bones, cranial cavity, facial bones.
  • Functions: Protects brain, supports entrances to digestive and respiratory tracts.
  • Associated Bones: Hyoid bone (neck) and auditory ossicles (6 small ear bones).

Vertebral Column (Spine)

  • Function: Protects the spinal cord, supports head and body.
  • Structure: 26 bones total (24 vertebrae, sacrum, coccyx).
  • Curves:
    • Primary (Accommodation) Curves: Thoracic and sacral, present at birth, accommodate internal organs.
    • Secondary (Compensation) Curves: Cervical and lumbar, develop post-birth, balance body weight for upright stance.
  • Regions:
    • Cervical: 7 vertebrae (C)
    • Thoracic: 12 vertebrae (T)
    • Lumbar: 5 vertebrae (L)
    • Sacrum and Coccyx: Attach axial skeleton to pelvic girdle.

Thoracic Cage (Rib Cage)

  • Components: Thoracic vertebrae, ribs, costal cartilage, sternum.
  • Functions:
    • Protects organs in thoracic cavity (thymus, heart, lungs).
    • Muscle attachment for breathing, vertebral column positioning, and pectoral girdles movement.
  • Ribs: 12 pairs, extend from thoracic vertebrae.

Conclusion

  • The chapter concludes with the introduction to chapter 8, focusing on the appendicular skeleton.
  • Appendicular Skeleton: Includes limbs and bones supporting limbs, discussed next.

Study Tips

  • Remembering Vertebrae Counts: Breakfast at 7 (cervical), lunch at 12 (thoracic), dinner at 5 (lumbar).
  • Lab Sessions Importance: Detailed examination and feature identification of axial skeleton bones during laboratory work.