shoulder joints

Question 0

torque (def)

Answer 0

tendency of force to create rotation or movement around an axis

Question 1

biomechanics (def)

Answer 1

application of physical laws on biological systems

Question 2

internal/ external force (defs)

Answer 2

internal force = muscles = effort

external force = weights = load

Question 3

COG

Answer 3

1. center of gravity/ center of mass

2. balance point where force of gravity is focused/ concentrated

Question 4

lever systems (3)

Answer 4

1. class I- see-saw (fulcrum is in middle of load and effort)
   eg- AO joint 
2. class II- external force is between axis and internal force
   eg- standing on toes- MTP joint is axis
3. class III- internal force is closer to axis- most of our joints
   eg- elbow

Question 5

shoulder girdle joints (4)

Answer 5

1. scapulothoracic
2. sternoclavicular
3. acromioclavicular
4. glenohumeral

Question 7

scapulothoracic
1 type of joint
3 movements

Answer 7

1. not really a joint- a “relationship” btwn median border or scapul and thoracic vertebrae
   movements:
2. ab/adduction (other joints called protraction/ retraction)- this is bringing scapula away from spine/ pinching shoulder blades together
3. elevation/ depression
4. up/ downward rotation- (glenoid fossa is point of reference)
   -bringing arm up and down

Question 8

sternoclavicular joint (9) 
 type of joint
 3 movements and axes
 3 ligaments
 4 ligaments

Answer 8

1. complex joint (ie has disc)- medial end of clavicle (manubrium) and sternum
2. this is the only joint to attach shoulder girdle and trunk
   movement (triaxial):
   
   3. elevation/ depression (z axis)
      this is convex moving on concave
      normal ROM: 45 deg/ 15 deg
   4. protraction/ retraction (y axis)
      concave moving on convex
      normal ROM: 15 deg
   5. posterior rotation of clavicle - to lift up arm (x axis)
      ligament support:
   6. costal clavicular
   7. ant/ post SC
   8. interclavicular
   9. subclavian muscle adds support

Question 9

acromioclavicular joint
type of joint
3 movements and axes
3 ligaments

Answer 9

1. complex joint (disc), triaxial
   movements:
2. medial/ lateral rotation (glenoid fossa is point of reference)
   winging of scapula
   (movement around Y axis)
   
   3. ant/ posterior tipping - point of reference is top of scapula
      (x axis)
   4. up and down rotation
      (bottom apex of scapula moving away from midpoint)
      z axis

ligamentous support:

1. sup/ inf AC ligament
2. conoid
3. trapezoid ligament (these two are coracoclavicular-ligament)

Question 9

scapula purposes (3)

Answer 9

1. maintains proper L-T (length- tension) relationships
2. maintains joint congruency at glenohumeral joint
3. contributes to total ROM

Question 10

scapulohumeral rhythm (9)
    (abduction 2 phases 1-6, accessory motions 7-9)

Answer 10

abduction:
1. phase I- 0-90 deg
(2.) 60 deg= GH joint, 30 deg = scapula movement
(3.) 25 deg SC/ 5 deg AC
4. phase II - 90-180 deg
(5.) 60 deg = GH joint, 30 deg = scapula movement
(6.) 5 deg SC/ 25 deg AC
accessory motions:
7. scapula winging
8. posterior tipping
9. abduction

Question 11

glenohumeral joint 
 type of joint
 4 movements and axes
 4 lig
how do dislocations happen?

Answer 11

1. triaxial
   movements:
   
   2. flex/ extend (x axis)
      normal ROM: 180/ 40-60 deg
   3. ab/ adduction (z axis) - bringing bicep to ear
      normal ROM- 180/ back to anatomical position
   4. internal/ external rotation (y axis)
   5. horizontal ab/adduction- start with shoulder abducted 90 deg, arm bent (y axis)

ligamentous support:

1. superior/ middle/ inferior glenohumeral ligament
2. coracohumeral ligament
3. clavicohumeral ligament

dislocation are usually anterior

Question 12

shoulder impingement (causes) (8)

Answer 12

1. common because such crowded space
2. coracoacromional ligament - protective ligament protecting supraspinatus and bursa
3. suprahumeral space - 10 mm, 5mm when abduct.
   - => impingement on supraspinatus
4. acromional shape and orientation
5. bone spurs
6. lack of scapula movement
7. weak rotator cuff muscles (pulls head down against deltoid pulling up)
8. inflammation of soft tissue

Question 14

MMT is testing what?

Answer 14

concentric (isometric) contraction