Week 8 - Shoulder bones and jts

Question 1

Glenoid Labrum function

Answer 1

• Deepens socket
• Limit accessory movement
• Increases congruency of GHJ
• Attachment for long head of biceps
  at the superior edge
• Labrum can be torn in dislocations
  or from biceps traction
• 59% of 1st time GHJ dislocations will
  include a Bankart lesion (anterior
  tear to labrum)1

Question 2

Glenohumeral ligament functions and how many

Answer 2

• Thickenings of capsule
• Prevents excessive movements inside the joint especially external rotation

4 - superior, middle anterior inferior & posterior inferior

Question 3

GLENOHUMERAL JOINT (GHJ) minor ligament functions (2)

Answer 3

Coracohumeral ligament:
Resists weight of arm
Keeps ball in socket

Transverse humeral ligament:
Converts intertubercular sulcus into the bicipital tunnel.
Holds synovial sheath around biceps in place

Question 4

Scapular humeral rhythm

Answer 4

When we abduct our shoulder, the GHJ, SCJ, ACJ and STJ all move to create 180 degrees of abduction.

Question 5

Scapular humeral rhythm movements of the joints and their degrees

Answer 5

2:1 ratio GH to ST movement

GHJ - 120 degrees abduction
GHJ - at 120 degrees it 45 degree ext. rot. to perform further abduction
SCJ - 25 degree elevation
ACJ - 35 degree upward rotation
SCJ - 25 degree posterior rotation
Scapular - 10 degree scap ext. rot.

25 + 35 degree = 60 scapular thoracic upward rotation

Question 6

Full shoulder abduction ratio

Answer 6

Ratio of 2:1
For 3 degrees of abduction
2 degrees occurs by GH joint
1 degrees occurs by scapular upward rotation

Question 7

Learn the humerus bony landmarks

Answer 7

Lesser tubercle
Greater tubercle
Intertubercular sulcus
Deltoid tuberosity
Lateral supra-epicondylar ridge
Lateral epicondyle
Medial epicondyle
Tuberosity of radius (radius)
Coronoid process (ulna)
Tuberosity of ulna (ulna)

Question 8

GLENOHUMERAL JOINT (GHJ)

Contractile structures that limit excessive movements

Non-contractile structures that limit excessive movements

Other structures

Answer 8

Contractile - rotator cuff muscles

Non-contractile - Glenoid labrum, ligaments

Other structures - Capsule - inferior folds, subacromial bursa