1. Naming Muscles

2. NAMING MUSCLES: Tips
Most skeletal muscles have names that describe some feature of the muscle.
Often several criteria are combined into one name.
Associating the muscle's characteristics with its name will help you learn and remember them.
The following are some terms relating to muscle features that are used in naming muscles.

3. Naming Skeletal Muscles
1 – Location of the muscle 2 – Shape of the muscle 3 – Size of the muscle 4 – Direction/Orientation of the muscle fibers/cells 5 – Number of Origins 6 – Location of the Attachments 7 – Action of the muscle

4. Location: ____________________ (chest) ____________________ (buttock)
____________________ (arm)
______________________(above)
______________________ (below)
_____________________(under or beneath)
_______________________ (lateral).

5. Shape: deltoid (_______________) rhomboid (like a rhombus
with equal and parallel sides)
latissimus (____________)
teres (__________)
trapezius (like a trapezoid, a four-sided figure with two sides parallel).

6. Size: ____________ (huge) _______________ (large)
__________________(long)
____________ (small)
__________________(short)

7. Direction of fibers: ____________ (straight) _____________ (across)
___________(diagonally)
______________(circular)

8. Number of origins: biceps (two heads) triceps (three heads)
                                     
Triceps Brachii
Origin
long head: infraglenoid tubercle of scapula
lateral head: upper half of the posterior surface of humerus medial head: distal two thirds of the posterior surface of humerus
biceps (two heads)
triceps (three heads)
quadriceps (four heads)

9. Origin and insertion:
sternocleidomastoid (origin on the sternum and clavicle, insertion on the mastoid process)
brachioradialis (origin on the brachium or arm, insertion on the distal end of radius at the styloid process)

10. Action: ____________(to abduct a structure)
_____________(to adduct a structure)
______________(to flex a structure)
_____________ (to extend a structure)
_____________ (to lift or elevate a structure)

11. How Muscles Attach to Bone
Indirect Attachment – ___________________
the _______________________ (sheath of connective tissue that surrounds the exterior of the muscle fibre) extends past the muscle as a ____________________ and then attaches to ____________________________.

12. How Muscles Attach to Bone
Direct Attachment – the epimysium adheres to and fuses with the periosteum

13. Review:
What is origin?
What is Insertion?

14. Try to Remember…
The origin usually stays fixed and the insertion moves closer to it
Origin
Insertion

15. 3 Basic Types of Muscle Contractions
Concentric
________________________________
Ex. biceps shorten when lifting an object
Eccentric
___________________________________
Ex. biceps lengthen as the same weight is
placed back on the ground
Isometric (static)
_________________________________________
Ex. trying to lift an immovable object.

16. Push or Pull???
Muscles _____________ by contracting and relaxing, muscles _________________
They work in pairs to create smooth movement, they are called _________________________(opposing pairs).

17. Agonist vs Antagonist?
Agonist–
Antagonist -

18. Example:
In elbow flexion, the biceps brachii will concentrically contract while the triceps brachii will eccentrically contract.

19. Fixators/Stabilizer
Muscles that are active isometrically (muscle does not shorten or lengthen) in order to fixate an area when the agonist contracts
Fixators/ Stabilizers -

20. Fixators/Stablizer
Example: When performing a push-up, the serratus anterior stabilizes the shoulder girdle during the downward stage in order to prevent adduction

21. Examples of opposing muscles and muscle groups AGONIST (Prime Mover)
ANTAGONIST
Elbow flexion
Biceps brachii
Triceps brachii
Shoulder abduction
Medial shoulder rotation
Knee extension
Wrist flexion
Dorsi flexion
Trunk flexion
Hip flexion