Anatomy & Physiology
A practical map of the body's structures and systems
Lesson 8 of 20
Skeletal system & bone
The skeleton supports the body, protects organs, provides levers for movement, stores minerals, and houses marrow. Bone is living tissue that remodels in response to biological signals and mechanical demands. Bones are grouped by shape, and the skeleton is commonly divided into axial and appendicular portions. These distinctions help orient palpation and movement study.
Key points
- Long bones have a shaft and ends; short, flat, irregular, and sesamoid describe other shapes.
- The axial skeleton includes skull, vertebral column, ribs, and sternum.
- The appendicular skeleton includes limb bones and the pectoral and pelvic girdles.
- Compact bone is dense; spongy bone has a trabecular framework.
- Red marrow forms blood cells; bone stores minerals including calcium and phosphate.
Key terms
- Axial skeleton
- Central skeleton including skull, spine, and thoracic cage.
- Appendicular skeleton
- Limb skeleton and the girdles that attach it to the axial skeleton.
- Compact bone
- Dense bone tissue forming a strong outer shell.
- Trabeculae
- Lattice-like structural elements within spongy bone.
- Bone remodeling
- Ongoing replacement of bone tissue through resorption and formation.
Memory tip
Axial: central support; appendicular: limbs and their attachments.
Clinical note
Palpable landmarks can guide orientation, but avoid forceful pressure over vulnerable bony areas.
Unit checkpoint
Lock it in: match the terms, then test yourself.