1. Naming Muscles

2. Muscles causing movement… ■ Skeletal Muscle – an organ made of several different types of tissue including muscle tissue, vascular tissue and nervous tissue

3. ■ Tendon – attaches the skeletal muscle to bone and pulls on bone when the muscle contracts

4. Joints ■ Skeletal muscles usually cross one or more joints. When a muscle contracts it pulls one bone closer to another ■ One bone stays in place while the other moves

5. Parts of a skeletal muscle ■ Origin – the attachment of a muscle on a stationary bone ■ Insertion – the attachment of a muscle on the movable bone ■ Belly – the fleshy portion of muscle between the origin and insertion

7. Group Actions ■ Most movements occur because groups of muscles work together, generally grouped in opposing pairs ■ Ex – abductors and adductors ■ Ex – extensors and flexors

8. ■ Agonist – muscle that produces the desired movement ■ Antagonist – muscle that relaxes when the agonist contracts ■ Synergists – another skeletal muscle that moves in the same general direction as the agonist increasing the force ■ Fixators – stabilize the origin and hold other joints still so the agonist can work more efficiently

10. Principle Skeletal Muscles ■ With over 700 skeletal muscles in the body, it will be easier to first learn the naming system and then learn specific muscles region by region

11. Naming Skeletal Muscles ■ Muscles are named according to the direction the fibers run, the size of the muscle, the shape of the muscle, the action the muscle produces, the number of origins the muscle has and/or the location of the muscle

12. Directions ■ The following terms refer to the direction the muscle fibers run in relation to the midline.

13. Rectus ■ Parallel to the midline

14. Transverse ■ Perpendicular to the midline

15. Oblique ■ Diagonal to the midline

16. Size ■ Relative to other muscles in that group

17. Maximus ■ Largest

18. Minimus ■ Smallest

19. Longus or Longissimus ■ Longest

20. Latissimus ■ Widest

21. Magnus ■ Large

22. Major ■ Larger

23. Minor ■ smaller

24. Vastus ■ great

25. Shape ■ General shape of the muscle

26. Deltoid ■ Triangle

27. Trapezius ■ Trapezoid

28. Serratus ■ Saw-toothed

29. Rhomboid ■ Diamond Shaped

30. Orbicularis ■ Circular

31. Pectinate ■ Comb-like

32. Piriformis ■ Pear shaped

33. Platys ■ Flat

34. Quadratus ■ square

35. Gracilis ■ slender

36. Action ■ Based on the action the muscle performs

37. Flexor/Extensor ■ Flexor – decreases the angle between bones ■ Extensor – increases the angle between bones

38. Abductor/Adductor ■ Abductor – moves a bone away from the midline ■ Adductor – moves a bone toward the midline

39. Levator/Depressor ■ Levator – elevates body part ■ Depressor – lowers body part

40. Supinator/Pronator ■ Supinator – turns palms up ■ Pronator – turns palms down

41. Sphincter ■ Decreases the size of an opening

42. Tensor ■ Makes a body part rigid

43. Number of Origins ■ Biceps – 2 heads ■ Triceps – 3 heads ■ Quadriceps – 4 heads

44. Location ■ Muscles named for the structures that they are by. Examples include the sternocleidomastoid muscle (runs from the sternum across the clavicle to the mastoid process) and the temporalis (near the temporal bone)