1. CHAPTER 5 Shoulder Complex

2. Shoulder girdle has 3 joints:
Introduction
Shoulder complex is the shoulder joint (GH joint) and the shoulder girdle.
Shoulder girdle has 3 joints:
Sternoclavicular
Acromioclavicular
scapulo-thoracic (aka scapulo-costal)
Only a functional joint – not a structural joint

3. General considerations:
The shoulder maximizes mobility, but at the sake of stability.
Primary purpose is to position hand for function.

4. Bones Scapula Flat triangular bone
Vertebral border positioned between T2 and T7
Provides location for glenohumeral (GH) muscles to originate and provides stable base from which GH joint can operate

5. Bones
Scapula
Works in concert with clavicle to enhance total shoulder range of motion (ROM)
Has many unique bony prominences:
Superior and inferior angles; spine; borders
Glenoid fossa; acromion; coracoid process
Supraspinatus/infraspinatus/subscapular fossas
Supraglenoid and infraglenoid tubercles

6. Bones
Scapula
Glenoid fossa
Deepened 50%
by glenoid labrum

7. Shoulder girdle movements
Joints
Shoulder girdle movements
Elevation/depression
Protraction/retraction
Upward rotation/downward rotation
Scapular tilting—A-P; M-L

8. Joints Sternoclavicular Connects upper extremity to axial skeleton
Saddle joint with three degrees of freedom
Elevation/depression
Protraction/retraction
Rotation
Acromioclavicular
Scapulothoracic

9. Joints Glenohumeral joint Ball and socket; three degrees of freedom
Inherently unstable
Humeral head more than twice the size of glenoid
Labrum deepens socket
Large capsule; redundant inferiorly

10. Joints Glenohumeral joint Capsular reinforcements
Superior/middle/inferior GH ligaments
Coracohumeral ligament
Long head of biceps/triceps
Rotator cuff tendons blend with capsule

11. Rotator Cuff
Supraspinatus
Infraspinatus
Subscapularis
Teres minor

12. Glenohumeral joint—osteokinematics
Joints
Glenohumeral joint—osteokinematics
Abduction/adduction—frontal—A-P axis
Flexion/extension—sagittal—M-L axis
Medial/lateral rotation—transverse—superior-inferior axis

13. Glenohumeral joint—arthrokinematics
Joints
Glenohumeral joint—arthrokinematics
Flexion/extension—spin
Abduction—superior roll; inferior glide
Lateral rotation—posterior roll; anterior glide
Medial rotation—anterior roll; posterior glide

14. Scapulohumeral Rhythm
Pairing of shoulder girdle movement with shoulder joint movement
Example: abduction of arm at shoulder joint
With
Upward rotation of shoulder girdle (scapula)

15. Muscles of the Shoulder Complex
Glenohumeral stabilizers
Supraspinatus
Infraspinatus/teres minor
Subscapularis
Biceps/triceps brachii

16. Muscles of the Shoulder Complex
Large movers
Deltoid
Latissimus dorsi
Teres major
Pectoralis major
Coracobrachialis

17. Function of Muscles of the Shoulder Complex
Synergistic muscle actions—force couples
Upward scapular rotation
Upper Trapezius—Lower Trapezius—Serratus Anterior
Downward Scapular Rotation
Pectoralis minor—levator scapulae—rhomboids
Shoulder elevation
Deltoid and rotator cuff

18. Summary
Shoulder is composed of three real joints; one pseudojoint
Shoulder provides extensive ROM
GH joint is inherently unstable
Rotator cuff and scapular muscles provide dynamic support to GH joint and scapula

19. Total shoulder motion is a result of:
Summary
Total shoulder motion is a result of:
Intricate balance between joints of shoulder
Proper functioning and synchronization of muscles
Shoulder injuries are common and occur when a “breakdown” of any one of the links occurs