1. Muscle Movements, Types, and Names Pg. 175 - 181
October 5, 2012

2. 5 Golden Rules of Skeletal Muscle Activity
All muscles cross at least one joint.
Typically, the bulk of the 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 contractions, the muscle insertion moves toward the origin.

3. Muscle Movement We have about 600 skeletal muscles
All skeletal muscles have at least two attachment points
Origin: immovable or less moveable bone
Insertion: moveable bone
The insertion ALWAYS moves TOWARD the origin

4. Types of Body Movements
Flexion: decreases the angle of the joint and brings two bones closer together
Typical of hinge joints and common in ball-and-socket joints
Extension: opposite of flexion – it increases the angle of the joint, and thus the distance between two bones
Straightening the knee or elbow
Extension greater than 180˚ is called hyperextension
Leaning your head/torso back to where your chin points to the ceiling

5. Rotation: movement of a bone around its longitudinal axis
Common of ball-and-socket joints
Describes the movement of the atlas around the axis (shaking your head no)

6. Abduction: moving a limb away from the midline of the body
Also includes fanning the fingers or toes to spread them apart
Adduction: opposite of abduction; moves a limb toward the body midline

7. Circumduction: combination of flexion, extension, abduction, and adduction
Commonly seen in ball-and-socket joints
Proximal end is stationary, distal end moves in a circle
The entire limb outlines a cone

8. Special Movements
Dorsiflexion: lifting the foot so that its superior surface approaches the shin (standing on your heels)
Similar to extending the hand at the wrist
Plantar flexion: depressing the foot (pointing the toes)
Similar to flexion of the hand

9. Inversion: turn your sole medially (towards the other foot)
Eversion: turn your sole laterally (away from the other foot)

10. Supination: SOUP! The palm faces up like you’re holding a bowl of soup
Radius and ulna are parallel
Pronation: palm faces down towards the ground
Radius and ulna form an X shape

11. Opposition: thumb can touch the tips of every other finger on the same hand

12. Types of Muscles Prime mover: has the most responsibility for movement
Antagonists: oppose or reverse a movement
When a prime mover is active, the antagonist is relaxed and stretched
Antagonists can have the chance to be prime movers
Synergists: help prime movers by producing the same movement or reduce undesirable movemetns
Fixators: specialized synergists; hold a bone still or stabilize the origin of a prime mover so all tension can be used to move the insertion bone

14. Naming Skeletal Muscles
Direction of the muscle fibers: rectus means all muscle fibers are straight whereas oblique means muscle fibers are slanted
Relative size of the muscle: maximus vs. minimus
Location of the muscle: temporalis and frontalis are on top of the temporal and frontal skull bones
Number of origins: biceps, triceps, quadriceps
Location of the muscle’s origin and insertion: sternocleidomastoid – origin on the sternum, origin on the clavicle, and insertion is the mastoid process
Shape of the muscle: deltoid means “triangular”
Action of the muscle: flexor, extensor, adductor