GHJ

Question 1

by how much does the labrum deepen the glenoid?

Answer 1

about 50%

Question 2

how many degrees of freedom at the GHJ? what are the movements?

Answer 2

3 degree of freedom but 4 pairs of movements

1. flx/ext
2. abd/add
3. ER/IR + horizontal abd/add

Question 3

what are the arthrokinematics of the GHJ during abduction?

Answer 3

convex on concave - sup roll, inf glide

Question 4

what are the arthrokinematics of GHJ flexion?

Answer 4

spin

Question 5

what are the arthrokinematics of GHJ ER?

Answer 5

convex on concave - post roll ant glide

Question 6

what are the arthokinematics of ER in anatomic position versus arm abducted to 90?

Answer 6

• anatomic position
  
  • post roll/ant slide
• 90 deg abduction
  
  • spin

Question 7

Describe the deltoid-RC Force Couple: Shoulder Abduction

Answer 7

• deltoid and supraspinatus roll
• subscap, teres minor, and infraspinatus slide

Question 8

what is seen clinically when a patient has a weak RC (supraspinatus specifically)?

Answer 8

the patient will throw their arm into adduction in order to allow their deltoid to take over abduction

Question 9

what happens if you fire the deltoid without RC muscles?

Answer 9

humeral head will be pulled into the coracoacromial arch

Question 10

what helps maintain deltoid LT relationship?

Answer 10

scapular upward rotation

Question 11

define the scapulohumeral rhythm

Answer 11

2:1 GH:ST movement

Question 12

what prevents GH subluxations?

Answer 12

static locking mechanism and conscious control of shoulder muscles