Chapter 11: Muscular System Flashcards
1
Q
Origin
A
Stationary Bone, usually proximal
2
Q
Insertion
A
Attachment of muscle’s other tendon to movable bone, usually distal
3
Q
Belly (Body)
A
Fleshy portion of a muscle between tendons (origin and insertion)
4
Q
Actions
A
Main movements that occur when muscle contracts
5
Q
Reverse muscle action (RMA)
A
Actions are reversed in specific actions
6
Q
Lever system and leverage
A
Bone acts as a lever (Rigid structure moves along a fixed point)
Muscle acts as a fulcrum (Fixed Pont)
7
Q
Effort
A
Causes movement
Force exerted by muscle contraction
8
Q
Load/resistance
A
Opposes movement
Weight of body part being moved
9
Q
Mechanical Advantage
A
only needs a small amount of force to move the load over a small distance
10
Q
Mechanical Disadvantage
A
Needs a large amount of force to move the load
11
Q
Lever types (3)
A
- First-class lever
- Second Class Lever
- Third Class Lever
12
Q
First class lever
A
scissors and seesaws
- produces either mechanical advantage or disadvantage
- Fulcrum is between Effort and the load
13
Q
Second class lever
A
wheelbarrow
1. Always produces a mechanical advantage
- sacrifices speed and Range Of Motion for force
- Load is between fulcrum and the effort
14
Q
Third class Lever
A
- produces mechanical disadvantage
- Favors speed and ROM over force
- effort between the fulcrum and the load
Most common in the body
15
Q
Prime Mover or agonist
A
Contracts, causes an action
16
Q
Antagonist
A
Stretches, yields to Prime mover
17
Q
Synergists
A
Aid movement of prime mover, prevent unwanted movement
18
Q
Fixators
A
stabilizes origin of prime mover, so it can move more efficiently
19
Q
Compartment
A
Group of skeletal muscles, blood vessels and associated nerves have a common function
- eg. upper limbs: Flexor compartment is anterior and extensor compartment is posterior
20
Q
Classification of Skeletal Muscles
A
Direction
Size
Shape
Action
of origins
Location
Origin and Insertion
21
Q
Orbitofrontalis
A
Frontal Belly: Superficial to frontal bone, raises eyebrow and Scalp anteriorly
Occipital Belly: Posterior part, superficial to occipital bone, Draws scalp posteriorly and
22
Q
orbicularis oculi
A
Closes eye
23
Q
Zygomaticus major
A
Smiling
24
Q
Buccinator
A
Forms cheeks
25
Orbicularis oris
Closes and protrudes lips, compresses lips against teeth and shapes lips during speech
26
*Masseter
strongest muscle of masication
Origin: Maxilla and zygomatic arch
Insertion: angle and ramus of mandible
Acton: Elevates mandible (closes mouth)
27
*Temporalis
Origin: Temporal Bone
Insertion: Coronoid process and ramus of mandible
Action: Elevates and retracts mandible
28
*Sternocleidomastoid
Origin:
sternal head --> manubrium of sternum
clavicular head --> medial third of clavicle
Insertion: Mastoid process of temporal bone and lateral half of superior nuchal line of occipital bone
Action: RMA
elevate sternum during forced inhalation
Bilaterally - flexes cervical portion of the vertebral column and flexes the head
Unilaterally - laterally flexes and rotates the head
29
*rectus abdominis
long muscle extending whole length of anterior abdominal wall
Origin: pubic crest and pubic symphysis
Insertion: cartilages of ribs 5-7 and the xiphoid process
Action: Flexes vertebral column (esp. lumbar), compresses abdomen to aid in defecation, urination, forced exhalation and childbirth (RMA: -exes pelvis on the vertebral column)
30
external oblique
superficial muscle - fascicles extend inferiorly and medially
31
Internal oblique
Intermediate muscle - fascicles extend at right angles to external obliques
32
transversus abdominis
deep muscle, fascicles directed transversely around abdominal wall
Together with internal and external oblique, structural arrangement of muscle fascicles in different directions provide considerate protection to abdominal viscera
Form linea alba
During forceful exhalation – compresses abdomen
33
diaphragm
important muscle that powers breathing - separates thoracic and abdominal cavities
Convex superior surface - forms floor of thoracic cavity
Concave inferior surface - forms roof of abdominal cavity
Contraction of diaphragm causes it to flatten and increases vertical height in thoracic cavity (inhalation)
Relaxation of diaphragm causes it to move superiorly and decrease in height in thoracic cavity (exhalation)
34
external intercostal
Elevate ribs during inhalation - expands thoracic cavity
During relaxation: depress ribs and decreases anteroposterior and lateral dimensions of thoracic cavity (exhalation)
35
Internal Inter costal
Decreases size of thoracic cavity during forced exhalation
36
Pectoralis minor
Draws scapula up towards thorax
37
*trapezius
extends from the skull and vertebral column medially and to the shoulder girdle laterally most superficial back muscle
Covers posterior neck region and superior portion of the trunk (found on both sides - form a diamond shape)
Origin: superior nuchal line of occipital bone, ligamentum nuchae and spines of c7-t12
Insertion: clavicle and acromion and spine of scapula superior fibers
Action: upward rotation of scapula middle fibers - adduction of scapula inferior fibers - depress and upward rotation of scapula superior and inferior fibers - upward rotation, stabilizes scapula
o RMA - superior fibers help extend head
38
*levator scapulae
Origin: transverse processes of c1-c4
Insertion: superior vertebral border of scapula
Action: elevates scapula and rotates downward
39
rhomboid major
elevates and adducts scapula rotates it downward stabilizes scapula
40
*pectoralis major
origin: clavicular head, sternum and costal cartilages of ribs 2-6, sometimes ribs 1-7 (sternocostal head)
Insertion: greater tubercle, lateral lip of intertubercular sulcus of humerus
Action: adducts and medially rotates arm at shoulder joint clavicular head - -exes arm sternocostal head extends -exed arm to side of trunk
41
latissimus dorsi
Action: extends, adducts and medially rotates arm at shoulder joint
Draws arm inferiorly and posteriorly o
RMA: elevates vertebral column and torso
42
Deltoids
origin (3):
1. acromial extremity of clavicle (anterior fibers)
2. Acromion of scapula (lateral fibers)
3. Spine of scapula (posterior fibers)
Insertion: deltoid tuberosity of humerous
Action:
1. lateral fibers abduct arm at shoulder joint
2. anterior fibers - -ex and medially rotate arm at shoulder joint
3. posterior fibers - extend and laterally rotate arm at shoulder joint
43
subscapularis
Medially rotates arm at shoulder joint
44
Supraspinatus
Origin: supraspinous fossa of scapula
Insertion: greater tubercle of humerus
Action: assists deltoid muscle in abducting arm at shoulder joint
45
infraspinatus
Laterally rotates arm at shoulder joint
46
teres major
Extends arm at shoulder joint assists adduction and medial rotation of arm at shoulder joint
47
Teres minor
Laterally rotates and extends arm at shoulder joint
48
biceps brachii
Origin (2):
1. Long head - tubercle above glenoid cavity of scapula
2. short head - coracoid process of scapula
Insertion: radial tuberosity of radius and bicipital aponeurosis
Action: Flexes forearm at elbow joint Supinates forearm at radioulnar joints Flexes arm at shoulder joint
49
Brachialis
Deep to biceps brachii, powerful -exor of the forearm "workhorse"
50
Brachioradialis
Flexes forearm at elbow joint - supinates and pronates forearm at radioulnar joints to neutral positon
51
*triceps brachii
Origin (3):
1. Long head - infraglenoid tubercle
2. Lateral head - lateral and posterior surface of humerus
3. medial head - posterior surface of humerus inferior to a groove for the radial nerve
Insertion: olecranon of ulna
Action: extends forearm at elbow joint, extends arm at shoulder joint
52
pronator teres
Pronates forearm at radioulnar joints and weakly -exes
53
supinator
supinates forearm at radioulnar joints use it when you screw in a screw driver or open a corkscrew
