1. Lever Systems: Bone-Muscle Relationships

2. Bone-Muscle Relationships: Lever Systems
Lever- rigid bar; free to turn about fixed point ex. bone
a. Fulcrum- fixed point; ^
ex. joint
b. Load- resistance moved; L
ex. part of body
c. Force- pull from contraction; F
ex. muscle

3. Bone-Muscle Relationships: Lever Systems
Mechanical advantage
Figure 10.2a

4. Bone-Muscle Relationships: Lever Systems
Mechanical disadvantage
Figure 10.2b

5. Lever Relationships
Effort farther than load from fulcrum equals mechanical advantage
Effort nearer than load to fulcrum equals mechanical disadvantage

6. Lever Systems: Classes
a. 1st Class- Fulcrum between Load & Force; seesaw;
stability
Ex. Head tilt
b. 2nd Class- Load between Fulcrum & Force; wheelbarrow; lift
Ex. Raising body with toes
c. 3rd Class- Force between Fulcrum & Load; shovel; rapid mov’t
Ex. Flex forearm

7. Lever Systems: Classes
Figure 10.3a

8. Lever Systems: Classes
Figure 10.3b

9. Lever Systems: Classes
Figure 10.3c

10. In this example the weight is situated between the force and the fulcrum
In this example the force is located between the weight and the fulcrum
In this case the fulcrum is located between the force and weight

11. Machines of the Body

12. Prime movers and synergist muscles

13. Agonist and antagonist muscles

15. Apart from assisting in locomotion does the muscular system play any other role?
Posture; this includes the erector spinae muscles and the muscles of the trunk.

20. Salient points
• Muscle groups are classified upon the the arrangement of the muscles fibres, this provides a wide range of muscle types.
• The origin of the muscle is that attachment at which the bone is stationary
• The insertion of the muscle is at that attachment where the bone is moving
• Muscle can have several different roles; they can be agonists, antagonists and synergists
• Not all muscles are involved in locomotion, they also enable other important bodily functions, for example, respiration, provide movement for the eye, assist in swallowing and speech

21. Major Skeletal Muscles: Anterior View
The 40 superficial muscles here are divided into 12 regional areas of the body
Figure 10.4b

22. Major Skeletal Muscles: Posterior View
The 27 superficial muscles here are divided into seven regional areas of the body
Figure 10.5b

28. Origin
Insertion