Anatomy and Physiology: The Skeletal System and Joints

Introduction

• Traditional songs about skeletal structure are oversimplified.
• Understanding the skeletal system involves more than memorizing bone names.
• Includes bones, cartilage, fibrous connective tissue, and joints.
• Joints: Meeting places between bones, more joints than bones in the body.
• Movement occurs when muscles contract across joints.

Human Skeleton Overview

• Divided into two major parts: Axial and Appendicular.

Axial Skeleton

• Skull
  • 8 Cranial and 14 Facial bones.
  • Functions: Protects brain, sensory functions, facial structure.
• Vertebral Column
  • 33 irregular bones, starting with Atlas vertebra.
  • Supports upper body and protects spinal cord.
• Thoracic Cage
  • 12 pairs of ribs and sternum.
  • Protects vital organs and provides muscle attachment.

Appendicular Skeleton

• Components: Upper and lower limbs, pectoral, and pelvic girdles.
• Similar setup in arms and legs: "One bone, two bones, lots of bones and digits."

Joints in the Human Body

• Classification: By structure and function.
  • Structural: Fibrous, cartilaginous, synovial.
  • Functional: Synarthroses (immovable), Amphiarthroses (partly movable), Diarthroses (fully movable).

Types of Joints

• Fibrous Joints
  • Dense connective tissue, mostly immovable.
• Cartilaginous Joints
  • United by cartilage, slightly movable.
• Synovial Joints
  • Freely movable, feature fluid-filled joint cavity.
  • Allow varied movements and prevent joint overheating.

Synovial Joint Movements

• Gliding Movements (e.g., wrist bones)
• Angular Movements
  • Flexion, extension, hyperextension.
  • Abduction, adduction, circumduction.
• Rotational Movements
  • Occur in ball-and-socket joints.
• Special Movements
  • Opposition, supination, pronation.
  • Unique to certain joints like thumb and jaw.

Conclusion

• Reviewed axial and appendicular skeleton.
• Covered structural and functional classifications of joints.
• Discussed types of movements facilitated by joints.

Acknowledgments

• Credits to the contributors and patrons of Crash Course.