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Understanding the Human Skeletal System
Oct 28, 2024
Anatomy and Physiology of the Skeletal System
Introduction
The skeletal system in humans is more complex than the simplified "toe bone's connected to the foot bone" song.
Consists of 206 bones, cartilage, fibrous connective tissue, and joints.
Skeletal system enables movement through muscle contraction across joints.
Divisions of the Skeleton
Axial Skeleton
Comprises 80 midline bones: skull, vertebral column, thoracic cage.
Skull: 8 cranial and 14 facial bones for brain protection and sensory functions.
Vertebral Column: 33 irregular bones, starting with atlas vertebra, supports body, protects spinal cord.
Thoracic Cage: 12 rib pairs and sternum, protects vital organs, supports muscles.
Appendicular Skeleton
Includes upper/lower limb appendages, pectoral, pelvic girdles.
Shared setup in limbs: three major segments (one bone, two bones, lots of bones, digits).
Joints
Joints are critical for movement, classified by structure and function.
Structural Classification
Fibrous Joints
: Dense connective tissue, mostly immovable, e.g., skull sutures.
Cartilaginous Joints
: Bones united by cartilage, limited movement, no joint cavity.
Synovial Joints
: Freely movable, separated by fluid-filled cavity.
Joint Movements
Types of Movement
Synarthroses
: Non-moving joints, e.g., cranial sutures.
Amphiarthroses
: Slightly moving joints, e.g., pubic symphysis.
Diarthroses
: Fully movable joints, e.g., knees, elbows.
Synovial Joint Features
Synovial fluid acts as lubricant, prevents joint friction.
Six configurations of synovial joints allow diverse movements.
Specific Joint Movements
Gliding Movements
: Flat surface glides over another, e.g., wrist joints.
Angular Movements
Flexion
: Decrease joint angle, bring bones together.
Extension
: Increase joint angle, move bones apart.
Abduction/Adduction
: Move limb away/toward body.
Circumduction
: Circular motion, combines flexion, extension, abduction, and adduction.
Rotational Movements
: Bone turns around its axis, e.g., shoulder and hip joints.
Special Movements
: Unique motions, e.g., thumb opposition, supination/pronation of palm.
Conclusion
Learning about the skeletal system is more effective through understanding its physiology and the various types of movements.
Thanks to contributors and patrons for supporting educational content creation.
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