Lecture: Muscle Mechanics

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Lecture: Muscle Mechanics
2012-03-28 22:22:30
Lecture Muscle Mechanics

Lecture: Muscle Mechanics
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  1. Define Skeletal Muscle functional groups
    1. Prime movers: provide the major force for producing a specfic movement

    2. Antognists: oppose or reverse a particular movement (muscles cannot push, only pull)

    3. Synergists (help prime movers): add force to a movement and reduce undersirable or unnecessary movement

    4. Fixators: synergists that immobilize a bone or muscle's origin
  2. How are skeletal muscles named?
    1. Location: bone or body region associated with the muscle

    2. Shape: ex- deltoid means triangle

    3. Relative size: ex- maximus, minimis, longus, brevis

    4. Direction of fibers or fascicles: ex- rectus, transversus, and onlique

    5. Number or origins: ex- bicepts means 2 origins, triceps have 3

    6. Location of Attachments: ex- sternocleidmastoid

    7. Action: ex- flexor or extensor
  3. Arrangement of fascicles
    Circular (Sphincters): organized in concentric rings, such as the orbicularis oris

    Convergent: converge toward a single tendon insertion, like the pectoralis major

    Parallel: paralell to the long axis of a straplike muscle, like the sartorius

    Fusiform: spindle shaped muscles with parallel fibers, like the biceps brachii

    • Pennate: looks like a feather, short fascicles attache obliquely to a central tendon running the length of the muscle, such as the rectus femoris
  4. Muscle Mechanics: Lever Systems
    Lever: rigid bar (bone) that moves on a fixed point or fulcrum (joint)

    Effort: force (supplied by the muscle contraction) apploed tp a lever to move a resistance (load)

    Load: resistance (bone, tissue, and any added weight) moved by the effort
  5. Lever systems: First class
    Fulcrum between load and effort

    • Like a pair of scissors
  6. Lever systems: second class
    Load between fulcrum and effort

    Like a wheelbarrel

  7. Lever systems: Third class
    effort applied bewtween fulcrum and load

    Like tweezers