1. SHOULDER COMPLEX

2. Extrinsic Shoulder Muscles
Review the following:
Pectoralis major
Pectoralis minor
Serratus anterior
Trapezius complex
Latissimus dorsi
Levator scapulae
Rhomboideus major
Rhomboideus minor

3. Sensory Supply to Shoulder
Supraclavicular nerves:
From cervical plexus
C3-4
Supply skin over clavicle and over the superior-lateral aspect of pectoralis major
Cutaneous branches of dorsal rami:
Penetrate deep and superficial back muscles
Supply skin on either side of midline of back

4. Shoulder Movements Elevation (scapula): Depression (scapula):
Levator scapulae and rhomboids
Depression (scapula):
Latissimus dorsi

5. Shoulder Movements Abduction (scapula): Abduction (shoulder):
Serratus anterior
Abduction (shoulder):
Middle deltoid
Biceps brachii assists
Adduction (scapula):
Middle trapezius
Adduction (shoulder):
Pectoralis major (clav)
Latissimus dorsi

6. Shoulder Movements Upward rotation (scapula):
Serratus anterior
Upper and lower trapezius (force couple)
Downward rotation (scapula):
Rhomboids
Levator scapulae

7. Quadrilateral Space Boundaries: Contents:
Inferior glenohumeral capsule.
Teres major.
Triceps longus.
Surgical neck of humerus.
Contents:
Axillary nerve.
Posterior circumflex humeral artery.

8. Shoulder Complex Joints
Sternoclavicular joint (SC)
Acromioclavicular joint (AC)
Glenohumeral joint (GH)

9. Sternoclavicular Joint (SC)
Plane synovial joint
Articulating surfaces:
Sternal end of clavicle
Articular notch on manubrium
First costal cartilage
3 degrees of freedom

10. SC Joint Movements Elevation and depression:
Occurs around AP axis
Elevation = 45 degrees
Depression = 15 degrees
Protraction and retraction:
Occurs around vertical axis
Protraction ROM = 15 degrees
Retraction ROM = 15 degrees
Rotation:
Occurs around transverse axis

11. Sternoclavicular Joint
Joint disc
Fibrocartilage meniscus
Attached to:
Clavicle inferiorly
Manubrium and first costal cartilage inferiorly
Ligaments:
Anterior/posterior sternoclavicular ligaments:
Check anterior/posterior movements of clavicular head.

12. SC Joint Ligaments Costoclavicular ligament: Interclavicular
Axis for elevation and depression
Axis for protraction and retraction
Main check for elevation
Interclavicular

13. Acromioclavicular Joint
Plane synovial joint
3 degrees of freedom
Articulation surfaces:
Convex facet on lateral end of clavicle
Concave facet on acromion

14. AC Joint Movements Scapular rotation:
Occurs around AP axis.
Winging of vertebral border of scapula:
Occurs around vertical axis.
Tipping of inferior angle of scapula:
Occurs around coronal axis.

15. Acromioclavicular Joint
Acromioclavicular ligaments:
Superior and inferior
Reinforce joint capsule
Coracoclavicular:
Trapezoid (lateral)
Conoid (medial)

16. Glenohumeral Joint Ball-and-socket joint Synovial Components:
Head of humerus
Glenoid fossa of scapula
Glenoid labrum
Fibrocartilage meniscus
Deepens articulating surface of glenoid fossa

17. Glenohumeral Joint Ligaments: Joint capsule: Glenohumeral
Coracohumeral
Coracoacromial
Joint capsule:
Very lax
Up to an inch of passive distraction

18. GH Joint Movements Flexion/extension of brachium:
Abduction/adduction of brachium:
Lateral/medial rotation of brachium:

19. Shoulder Complex Components
Scapulothoracic joint:
Not a true anatomic joint
Represented by sliding of scapula on thoracic cage
Coracoacromial arch:
Components:
Acromion
Coracoid process
Coracoacromial ligament
Subacromial/subdeltoid bursae

20. ROTATOR CUFF

21. Rotator Cuff
Composed of four muscles whose tendons of insertion form a partial “cuff” around the head of the humerus.
Involved in snubbing and rotating head of humerus

22. Rotator Cuff Components
Supraspinatus S
Infraspinatus I
Teres minor T
Subscapularis S

23. Rotator Cuff

24. Rotator Cuff

25. Scapulohumeral Rhythm
Refers to relatively uninterrupted movement of upper extremity from dependent position to full abduction.
Requires simultaneous and coordinated movements of all the previous-named joints.

26. Scapulohumeral Rhythm
ROM:
Full abduction:
180 degrees
Contributed by glenohumeral joint:
120 degrees
Contributed by scapulothoracic movement:
60 degrees:
Sternoclavicular joint = 40 degrees
Acromioclavicular joint = 20 degrees
Ratio of GH to ST = 2:1

27. Steps in Arm Abduction Movement (searching) of scapula:
Serratus anterior clamps scapula to thoracic wall
Snubbing of head of humerus into glenoid fossa:
Rotator cuff muscles
First few degrees of abduction:
Supraspinatus
External rotation of humerus:
Infraspinatus

28. Clinical Applications
Deltoid paralysis:
Axillary nerve
Serratus anterior paralysis:
Long thoracic nerve
Tears in rotator cuff
Supraspinatus most often torn: