4. Movements of Muscles
• Extension: increasing angle between body parts
• Flexion: decreasing angle between body parts
– Dorsiflexion vs. Plantarflexion
– Inversion vs. Eversion
• Abduction: moving away from the median plane
• Adduction: moving towards the median plane
• Rotation: moving around the long axis
• Circumduction: moving around in circles
5. • Elevation: lifting body part superiorly
• Depression: moving body part inferiorly
• Supination: rotating forearm laterally
• Pronation: rotating forearm medially
• Protraction: Anterior movement
• Retraction: Posterior movement
Movements of
Muscles
11. •A skeletal muscle has two or more
attachments. The attachment that moves the
least is referred to as the origin, and the one
that moves the most, the insertion
•The fleshy part of the muscle is referred to
as its belly.
•The ends of a muscle are inserted into bones,
cartilage, or ligaments by cords of fibrous
tissue called tendons.
Skeletal Muscle
15. The biceps is tri-articulate,
meaning that it works
across three joints. The
most important of these
functions are to supinatethe
forearm and flex the elbow.
22. • Agonist: one muscle or group of muscles actively
contract to produces particular movement of a joint
and is/are called a primary mover (eg) biceps brachii is
main flexor of forearm
• Antagonist: Any muscle that opposes the action of the
prime mover is an antagonist. Before a prime mover
can contract, the antagonist muscle must be equally
relaxed. (eg) triceps brachii is antagonist to biceps
brachii
Functional Muscle Groups
(Skeletal Muscle action)
23. The biceps is tri-articulate,
meaning that it works
across three joints. The
most important of these
functions are to supinatethe
forearm and flex the elbow.
24. Example 2 for Agonist and AntagonistExample 2 for Agonist and Antagonist
25. Fixators: A fixator contracts isometrically (i.e., contraction increases the tone
but does not in itself produce movement) to stabilize the origin of the prime
mover so that it can act efficiently. For example, the muscles attaching the
shoulder girdle to the trunk contract as fixators to allow the deltoid to act on the
shoulder joint.
Functional
Muscle
Groups
(Skeletal Muscle
Action)
26. • Synergists: : In many locations in the body the prime mover muscle crosses several
joints before it reaches the joint at which its main action takes place. To prevent
unwanted movements in an intermediate joint, groups of muscles called synergists
contract and stabilize the intermediate joints. For example, the flexor and extensor
muscles of the carpus contract to fix the wrist joint, and this allows the long flexor and
extensor muscles of the fingers to work efficiently
Functional Muscle Groups (Skeletal Muscle Action)
27. Functional Muscle Groups
• Agonist = primary mover of a muscle, major
response produces particular movement
– (eg) biceps brachii is main flexor of forearm
• Antagonists = oppose/reverse particular
movement, prevent overshooting agonistic
motion
– (eg) triceps brachii is antagonist to biceps brachii
28. Functional Muscle Groups
• Synergists = muscles work together, adds extra force to
agonistic movement, reduce undesirable extra movement
– (eg) muscles crossing 2 joints
• Fixators = a synergist that holds bone in place to provide
stable base for movement
– (eg) joint stablilizers
29. Naming Muscles
• Location: (eg) brachialis = arm
• Shape: (eg) deltoid = triangle
• Relative Size: (eg) minimus, maximus, longus
• Direction of Fascicles: (eg) oblique, rectus
• Location of Attachment: (eg) brachioradialis
• Number of Origins: (eg) biceps, quadriceps
• Action: (eg) flexor, adductor, extensor
30. Muscle System: uses levers to move
objects
• How it works: A rigid bar moves on fixed point when a
force is applied to it, to move object
• Lever = rigid bar = bone
• Fulcrum = fixed point = joint
• Effort = force applied = muscle contraction
• Load = object being moved = bone
31. Muscle Basics to Remember
• 3 Types: Skeletal, Cardiac, Smooth
• Origin vs. Insertion
• Direct vs. Indirect Attachments
– direct = right onto bone
– indirect = via tendon/aponeurosis
• more common
• leave bony markings = tubercle, crest, ridge, etc.
• Sometimes attach to skin
