UNIT 2 - chapter 9 Flashcards
Shoulder girdle
Scapula and clavicle, acromioclavicular and sternoclavicular joints
Shoulder joint
Scapula and humerus, glenohumeral joint
Shoulder bones, joints, ligaments
Scapular - resting between ribs 2-7 Clavicle Sternum, ribs attach Humerus Rib cage, scapula glides on
Joints Glenohumeral Sternoclavicular Acromioclavicular Scapulothoracic Articulation
Ligaments
Sternoclavicular
Acromioclavicular
Coracoidacromial
Scapulothoracic articulation
Not a true joint, provides motion and flexibility, scapula not really attached to thorax
Glenohumeral joint
shoulder joint, most mobile in the body, external and internal rotation, flexion/extension, abduction/ adduction, horizontal abduction and adduction
Sternoclavicular joint
The direct attachment of the shoulder girdle to the trunk Clavicle moves, sternum doesn't 3 subtle degrees of motion: 1. elevation/ depression 2. protraction/ retraction 3. rotation synovial joint
Articular disc
shock absorber, attached in 2 places acts like a hinge on a door that swings in both directions
Costoclavicular ligament
limits the elevation of the clavicle
Sternoclavicular ligament
provides reinforcement of joint, limits anterior/posterior movement
Interclavicular ligament
On top of the manubrium, connect the clavicles, limits depression
Acromioclavicular joint
Connects with acromion process and lateral end of the clavicle
weak joint
increased mobility
Acromioclavicular ligament
superior and inferior, prevents dislocation of clavicle by holding it to the acromion
Accessory ligaments of the acromioclavicular joint
Coracoclavicular ligament: prevents backwards movement of the scapula and limits rotation
Coracoacromial ligament: forms a protective arch over the humerus, provides support to the humeral head
Scapulothroacic
Refers to movements of the scapula and clavicle (acromioclavicular and sternoclavicular joints)
Elevation/ depression linear
Protraction/ retraction linear
Upward and downward rotation angular/ rotational
INFERIOR angle is reference point
scapuar tilt
Scapular winging
disfunction, loss of muscle function, loss of stabilizing muscles, scapular lifts away from rib cage, noticeable at the vertebral border
Companion motions
Whenever there is shoulder joint movement, there must/ will be scapular movement
Shoulder joint Flexion Extension Hyperextension Abduction Adduction Medial rotation Lateral rotation Horizontal abduction Horizontal adduction
Shoulder girdle Upward rotation, protraction Downward rotation, retraction Scapular tilt Upward rotation Downward rotation Protraction Retraction Retraction Protraction
Impairment in one must result in dysfunction at the other
Scapulohumeral rhythm
initial 30* of shoulder joint movement, only pure movement happening at shoulder joint
After those 30, for every 2 of shoulder elevation (flexion or abduction), the scapula must rotate upward by 1*
2:1 ratio
Angle of pull
Vertical pull- elevation, depression, greater up down movement
Horizontal- protraction, retraction, greater in out
MM with equal pull, can play a role in both
Prime movers
Retraction
Middle trapezius, rhomboids
Protraction
Serratus anterior, pectoralis minor
Elevation
Upper trapezius, levator scapula, rhomboids
Depression
Lower trapezius, pectoralis minor
Upward rotation
Upper and lower trapezius, serratus anterior
Downward rotation
Rhomboids, levator scapulae, pectoralis minor
Scapular tilt
Pectoralis minor
Upper trapezius
Action: 1 degree of scapular elevation, and upward rotation, 2 degrees of retraction
Antagonist to the lower trap, elevation
Agonist with the lower trap, rotation
Middle trapezius
Action: scapular retraction
horizontal line of pull
Lower trapezius
Action: depression, and upward rotation
Antagonist with upper trap, depression
Agonist with the upper trap, rotation
Levator scapula
Action: scapular elevation, downward rotation
Rhomboids
Action: prime mover in retraction and elevation, also rotate scapular downward
oblique line of pull
2 muscle major and minor
Serratus anterior
Goes under the scapula, and mm goes between ribs and scapula
Horizontal line of pull
Action: Protraction, lower fibers also upwardly rotate, rounding back out, keeps scapula against rib cage (winging)
Pectoralis minor
Action: scapular depression, downward rotation, and scapular tilt
Line of pull: Downward diagonal, vertical
Force couples
Muscles that are pulling in different directions but produce the same motion
Scapular upward rotation
upper trap pulls up, lower trap pulls down, serratus anterior pulls inferior angle outward horizontally (forward)
Scapular downward rotation
Pec minor pulls down, rhomboids pull in, and levator scapula pulls up
Inferior angle to rotate downward
*Used when needed to bring arm down forcefully
Reversal of muscle action
Occurs when distal part of body, is fixed in closed chain movement
