1. Body movements

2. 5 Golden Rules of Skeletal Muscle Activity
All muscles cross at least one point.
Typically, the bulk of muscle lies proximal to the joint crossed.
All muscles have at least two attachments: the origin and the insertion
Muscles can only pull, they never push
During contraction, the muscle insertion moves toward the origin.

3. Types of Body Movements
Every one of our 600 muscles is attached to bone or another connective tissue structure at no less than 2 points
Origin
Attached to the immovable or less movable bone
Insertion
Attached to the movable bone
When the muscle contracts, the insertion moves toward the origin
Muscles of the face are attached to skin.

4. Body movement occurs when muscles contract across joints,
The type of movement depends on
The mobility of the joint
Where the muscle is located in relation to the joint

5. Movements Produced by Muscle Contractions
Flexion – movement reduces the angle between two bones at their joint.
Bending the knee or elbow
Extension – opposite of flexion – increases the angle at a joint.
Straitening the knee or elbow
Abduction – moving a body part away from the midline of the body.
Adduction – moving a body part toward the midline of the body.
Rotation – movement of a body part around an axis.
Shaking your head

7. Movements Produced by Muscle Contractions
Supination – refers to hand position – movement turns palm up to the anterior position (anatomical position).
Pronation – palm of hand turned posteriorly.
Dorsiflexion – top of foot is elevated with toes pointing upward.
Plantar flexion – foot directed downward (standing on your toes).

8. Types of Muscles
Prime movers (agonist) – provide the major force for producing a specific movement
Antagonists – oppose or reverse a particular movement (will be on opposite side of the joint and inactive while agonist is active))
Synergists
Add force to a movement and reduce undesirable or unnecessary movement. Will stabilize one joint if a muscle crosses two joints.
Synergists that immobilize a bone or muscle’s origin are called fixators. (ex. scapula is held to axial skeleton by fixators that can immobilize it)

9. Naming Skeletal Muscles
Direction of
Fibers
Location
Size
Number Of
Origins
Shape
Origin
&
Insertion
Action

10. Naming of the muscle
Location of muscle – bone or body region associated with the muscle
Shape of muscle – e.g., the deltoid muscle (deltoid = triangle)
Relative size – e.g., maximus (largest), minimus (smallest), longus (long)
Direction of fibers – e.g., rectus (fibers run straight), transversus, and oblique (fibers run at angles to an imaginary defined axis)

11. Direction of Muscle Fibers
Relative to the Midline
RECTUS = parallel to the midline
Rectus Abdominus
TRANSVERSE = perpendicular to midline
Transverse Abdominus
OBLIQUE = diagonal to midline
External Oblique

12. Location Structure near which muscle is found
FRONTALIS = near FRONTAL bone
OCCIPITALIS = near OCCIPITAL bone

13. Size Relative Size of Muscle MAXIMUS = largest MEDIUS = middle
Gluteus Maximus
MEDIUS = middle
Gluteus Medius
MINIMUS = smallest
Gluteus Minimus
LONGUS = longest
Fibularis Longus
BREVIS = short
Fibularis Brevis
TERTIUS = shortest
Fibularis Tertius

14. Number of Origins Number of tendons of origin BICEPS = Two
Biceps Brachii
Biceps Femoris
TRICEPS = Three
Triceps Brachii
QUADRICEPS = Four
Quadriceps Femoris

15. Shape Relative Shape of the Muscle DELTOID = triangular shape Δ
TRAPEZIUS = trapezoid shape  SERRATUS = saw- toothed ♒
RHOMBOIDEUS = rhomboid shape 
TERES = round ○

16. Origin & Insertion Origin – attachment to an immoveable bone
Insertion – attachment to a movable bone
ILIO COSTALIS= attaches to the ilium & ribs (costal = ribs)

17. Action NAME ACTION EXAMPLE FLEXOR EXTENSOR ABDUCTOR ADDUCTOR LEVATOR
Decrease angle at a joint
Flexor Carpi Radialis
EXTENSOR
Increase angle at a joint
Extensor Carpi Ulnaris
ABDUCTOR
Move bone away from midline
Abductor Pollicis Longus
ADDUCTOR
Move bone toward midline
Adductor Longus
LEVATOR
Produce upward movement
Levator Scapulae
DEPRESSOR
Produce downward movement
Depressor Labii Inferioris
SUPINATOR
Turn palm upward/anterior
Supinator
PRONATOR
Turn palm downward/posterior
Pronator Teres