Ch 6.4

• • types of body movements

  ◦ Two points: an origin (attached to immovable bone) and insertion (attacked to movable bone)

  ◦ Flexion: movement that brings 2 bones closer together

  ◦ Extensions: movement that increases the distance between 2 bones

  ◦ Rotation: movement of a bone around its longitudinal axis

  ◦ Abduction: moving a bone away from the middle of a body

  ◦ Adduction: moves a bone towards the middle of a body

  ◦ Circumduction: a combination of the first four (doing arm circles)
• • Special movements

  ◦ Dorsiflexion/plantar flexion: up and down movement of the foot

  ◦ Inversion/eversion: turning the feet to opposite sides

  ◦ Supination/pronation: turning the palm to either face up or down

  ◦ Opposition: moving the thumb to touch the other fingertips
• Interactions of Skeletal muscles in the body

  • muscles can only pull, so muscles have to be able to reverse each other

  • Prime mover: muscles that cause a movement

  • Antagonists: muscles that reverse a movement

  • Synergistic: produce the same movement as prime movers and reduce unwanted movements

  • Fixations: hold bones still/stabilize origins
• Naming skeletal muscles

  • Criteria

  ◦ Direction of muscle fibers (straight, slanted, etc)

  ◦ Relative size (largest, smallest)

  ◦ Location of muscle (named after bones)

  ◦ Number of origins (tri, quad, bi, etc)

  ◦ Location of muscle origin/insertion (sternum, clavicle, etc)

  ◦ Shape of muscle (trapezoid, deltoid or triangular)

  ◦ Action of muscle (flexor, extensor, etc.)
• Arrangement of fascicles

  • Circular: arranged in rings

  • Convergent: converge towards a tendon

  • Parallel: fascicles run parallel

  • Fusiform: spindle shaped

  • Pennate: featherlike