-Muscles always pull and never push bones…
***Meaning during a joints movement phase muscles causing the movement can only pull the bones toward each other…they cannot push the bones toward each other.
Example:
-Elbow flexion
*Muscle responsible is the biceps brachii (prime mover).
*Pulls insertion towards origin radial tuberosity toward the coracoid process
Triceps Brachii (antagonist):
-This muscle does not “push” the joint open during muscle contraction… in this example it does allow the action to occur…

Muscle Movements…
Muscle Movements:
Prime mover – Muscle with the major responsibility for a certain movement
Antagonist – Muscle that opposes or reverses the action of a prime mover
Synergist – Muscle that aids a prime mover in a movement
***Synergists do a similar movement to the prime mover, but to a lesser degree
***Synergists also help reduce undesirable movements… (muscles that stabilize the wrist during elbow flexion)
Fixator Muscles – Stabilizes one part of the body during the movement of another
***Specifically stabilizes the origin bone during movement.
***Examples would be the erector spinea group of muscles that keep you upright during movement

Naming Muscles…
1) Direction of the Muscle Fibers:
- Named in reference to an imaginary line (usually the midline of the body)
*** Example:
1) Rectus means “Straight”
- Rectus Femoris = muscle fibers of the thigh run parallel to that imaginary line
2) Obliques means neither parallel nor perpendicular to the long axis of a body or limb
- External Obliques = muscle fibers run at an “angle” to the midline

Naming Muscles…
2. Relative Size of the Muscle
Maximus = largest
Minimus = smallest
Longus = longest
*** Example:
1) Gluteus Maximus:
- Largest of the gluteal muscles (medius / minimus)
2) Gluteus Minimus:
- Largest of the gluteal muscles
3) Extensor Pollicus Longus:
- Longest of the extensor muscles of the posterior lower arm.

Naming Muscles…
3. Location of the Muscle
Named for the bone with the muscles are associated .
*** Example:
Temporalis = Overlies the temporal bone of the skull
Femoris = Overlies the femur
Anterior Tibialis = Overlies the anterior portion of the tibia
Sternocliedomastoid = Overlies the sternum, clavicle and mastoid processes
4. Number of Origins
Name based on the number of attachment sites (heads) that it has with bones
*** Example:
Biceps = two origins
Triceps = three origins
Quadriceps = four origins

Naming Muscles…
5. Location of the Muscle’s Origin and Insertion
Named for their attachment sites to bones.
*** Example:
Sternocleidomastoid
 Origin on sternum (Sterno—) and Clavicle (—cleido—)
 Insertion on mastoid process of temporal bone (—mastoid)
6. Shape of the Muscle
Named for the distinctive shape that some muscles have.
*** Example:
Deltoid: Deltoid means “triangular”
Rhomboideus Minor: Rhomboid shaped muscle “
A four-sided shape where all sides have equal length, also opposite sides are parallel and opposite angles are equal. (found deep to tapezium, which would be another good exmaple)

Naming Muscles…
7. Action of the Muscle
Named for actions such as flexion, extension, adduction and abduction…
*** Example:
Adductor Longus = adducts the femur
Extensor Digitorum Longus = Extends the fingers (found on posterior forearm area)
Extensor Digitorum Longus: = Extends the fingers (found on posterior forearm area)