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)