Unit 7/8 - intro to divisions of skeletal system

Two mains groups of the skeleton

1. Axial skeleton

   • bones from head to bottom of vertebral column

2. appendicular skeleton

   • bones of limbs and girdles that attach to axial skeleton

Musculoskeletal system

• muscular and skeletal system combined

  • Facilitate movement

5 main types of bones

1. Long bones

2. Short bones

3. Flat bones

4. Sesamoid bones

5. Irregular bones

Long bones

• longer than wide

• Curved to absorb shock evenly

Short bones

• as long as they are wide

• Mostly spongy BT surrounded by thin compact BT

Flat bones

• thin plates of compact bone

• Spongy bone interior

Sesamoid bones (seed like)

• thin, small

• Develop in areas of high mechanical stress

• Protect tendons (muscle to bone) by regulating tension during movement

Irregular bones

• irregularly-shaped or distributed

Surface marking - depressions and openings

• provide passage for blood vessels and nerves

  • Foramina, fossae, meati

Surface marking - processes, projections, outgrowths

• attachment points for ligaments and tendons

  • Condyles, facets, heads, crests, processes