1. The Shoulder Joint

2. Scapulohumeral Rhythm
Function:
Maximize ROM
Maintain glenoid fossa in optimal position
Maintain optimal length-tension relationship

3. Scapulohumeral Rhythm
1800 = 1200 G-H S-T
G-H:S-T = 2:1 over entire range

4. Scapulohumeral Rhythm Pre-phase/Setting
Inconsistent amount of scapula movement  Proximal STABILITY for distal mobility
G-H  or 300 abduction
Total = (all G-H motion)

5. Scapulohumeral Rhythm Phase I / S-T Motion
Trapezius (upper & lower) & Serratus Anterior (upper & lower) contract
Coracoclavicular ligament tightens (locks AC joint)

6. Scapulohumeral Rhythm Phase I / S-T Motion
Clavicle elevates ~ 300 thru SC joint
Costoclavicular ligament tightens
Tipping and 100 of winging

7. Scapulohumeral Rhythm Phase I / S-T Motion
Total motion following Phase I:
300 of scapula rotation occurring at SC jt.
~ 300 of G-H movement

8. Scapulohumeral Rhythm Phase I / S-T Motion
Total elevation =
(pre-phase G-H)
300 (S-T rotation)
+ 300 (G-H movement)
90 – 1200 of total elevation

9. Scapulohumeral Rhythm Phase II / A-C Motion
Taut coracoclavicular ligament pulls down on coracoid
Pulls conoid tubercle of clavicle down
Rotation of clavicle about long axis

10. Scapulohumeral Rhythm Phase II / A-C Motion
Rotation of scapula about axis through A-C joint
200 tipping / 400 winging

11. Scapulohumeral Rhythm Phase II / A-C Motion
Total elevation =
(pre-phase + phase I)
300 (S-T rotation)
(G-H movement)
1800

12. Scapulohumeral Rhythm Summary
0 to 900 = 600 GH / 300 SH about SC joint
900 to 1800  = 600 GH / 300 SH about AC joint

13. Acromioclavicular Sprain
Plane-synovial joint
Intraarticular disk – degenerates w/ age
Separation

14. Acromioclavicular Sprain
Mechanisms:
Direct force
Indirect force (less frequent)
outstretched arm

15. Acromioclavicular Sprain
I: sprain of AC ligaments
II: tear of AC ligament / sprain of coracoclavicular

16. Acromioclavicular Sprain

17. Acromioclavicular Sprain
III: tear of AC and coracoclavicular ligaments
IV: torn ligaments / posterior displacement of clavicle

18. Acromioclavicular Sprain

19. Acromioclavicular Sprain
V: torn ligaments / inferior displacement of clavicle
VI: torn ligaments / clavicle driven into subacromial / subcoracoid position

20. Acromioclavicular Sprain

21. Glenohumeral Joint Stability - intracapsular pressure (20-32 lbs.)
Concavity compression
Capsuloligamentous structures

22. Glenohumeral Joint
Stability
Scapulohumeral balance ()

23. Glenohumeral Joint - stable

24. Glenohumeral Joint -unstable

25. Glenohumeral Joint
Dislocation
> 90% anterior
Indirect
Direct

26. Glenohumeral Joint

27. Glenohumeral Joint

28. Impingement Supraspinatus tendon & subacromial bursa
Acromion and coracromial ligament/arch

29. Impingement Repetitive (< 35 y.o.) Degenerative (> 35 y.o)
spur formation
capsular thinning
 tissue perfusion
muscular atrophy

30. Repetitive Impingement
Repeated abduction  stresses capsuloligamentous & musculotendinous
Tissue microtrauma  tissue failure 
GH instability  subluxation

31. Impingement Classification: I. Isolated impingement w/ no instability
II. Overuse 20 overhead activities
instability w/ secondary impingement
III.  II but w/ generalized (systemic) ligamentous laxity
IV. Traumatic – indirect or direct

32. Mechanisms of RTC Impingement
Extrinsic - forces outside RTC
structural characteristics of subacromial space
Intrinsic - inflammatory changes within the cuff

33. Extrinsic Structural acromion shape hooked > flat or curved
Spurs  stress risers

34. Extrinsic
Structural
Supraspinatus outlet

35. Intrinsic Inherent due to compromised blood flow 20:
Impingement pressures
Avascularity

36. Risk Factors Awkward / static postures Heavy work Direct load bearing
Repetitive UE movement
Overhead movements

37. Populations
W/C athletes
Pitchers
Swimmers

38. RTC Rupture Inflammation  microtearing  partial or full rupture
Compromised tissue integrity & muscle fatigue  altered movement patterns

39. Kinematic Patterns w/ RTC Tears
I – stable fulcrum – supraspinatus & part of infra  normal motion / near-normal strength
II – unstable fulcrum – supraspinatus & infra and TM  disruption of force couples

40. Kinematic Patterns w/ RTC Tears
III – captured fulcrum – supraspinatus, post cuff, subscapularis  centering of humeral head  humeral elevation
IV – unstable fulcrum – supraspinatus & complete subscapularis  disruption of force couples  poor elevation