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The Shoulder Complex . The Shoulder Complex. General Structure & Function Structure & Function of Specific Joints Muscular Considerations Specific Functional Considerations Common Injuries. The Shoulder Complex. General Structure & Function Structure & Function of Specific Joints
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The Shoulder Complex • General Structure & Function • Structure & Function of Specific Joints • Muscular Considerations • Specific Functional Considerations • Common Injuries
The Shoulder Complex • General Structure & Function • Structure & Function of Specific Joints • Muscular Considerations • Specific Functional Considerations • Common Injuries
General Function • Provides very mobile, yet strong base forhand to perform its intricate gross and skilled functions • Transmits loads from upper extremity to axial skeleton
Shoulder Complex Movements • Shoulder Girdle • Elevation & depression • Protraction & retraction • Upward & downward rotation • Upward tilt • Shoulder (glenohumeral) • FL, EXT, HyperEXT • ABD, ADD, HyperADD, HyperABD • MR, LR, HorizontalABD, HorizontalADD
Abduction/Lateral Tilt (Protraction) Linear Movement Frontal Plane Angular movement Transverse Plane Adduction/Reduced Lateral Tilt (Retraction)
Depression Elevation Linear Movement Frontal Plane
Downward rotation Upwardrotation
Shoulder Complex Movements Upward tilt Reduction of Upward Tilt Angular movement Sagittal plane
Limited by capsular torsion Limited by bony impingement of greater tubercle on acromion
Large ROM Due To: • Poor bony structure • Poor ligamentous restraint • Scapulohumeral cooperative action
The Shoulder Complex • General Structure & Function • Structure & Function of Specific Joints • Muscular Considerations • Specific Functional Considerations • Common Injuries
Structure & Function of Specific Joints • Sternoclavicular Joint • Acromioclavicular Joint • Scapulothoracic Joint • Glenolhumeral Joint • Coracoacromial Arch
Sternoclavicular Joint: Bony Structure Poor Diarthrodial Biaxial
Sternoclavicular Joint: Capsule Very strong
Sternoclavicular Joint: Interclavicular Ligament Resists superior & anterior (posterior portion) motion
Sternoclavicular Joint: Sternoclavicular Ligament Resists anterior (PSL), posterior (ASL), & superior motion
Sternoclavicular Joint: Costoclavicular Ligament Resists upward and posterior motion
Sternoclavicular Joint: Accessory Structures Resists medial & inferior displacement via articular contact
Sternoclavicular Joint: Articular Surfaces Medial end of clavice is convex Clavicular facet is reciprocally shaped
Sternoclavicular Joint: Motions Axial Rotation: 50° EL/DEP: 35° PROT/RET: 35°
Sternoclavicular Joint: Motions Frontal plane Elev/Dep Sagittal plane Post Rot Horizontal plane ProT/ReT Ant/Post axis Vertical axis
Acromioclavicular JointBony Structure Poor Diarthrodial Nonaxial
Acromioclavicular Joint:Joint Capsule Very weak
Acromioclavicular JointAcromioclavicular Ligament Resists axial rotation & posterior motion
Acromioclavicular JointCoracoclavicular Ligament Resists superior motion
Acromioclavicular JointAccessory Structures Articular disc
Acromioclavicular Joint: Motion Little relative motion at AC joint UR/DR: 60° EL/DEP: 30° PROT/RET: 30-50°
Acromioclavicular Joint: Osteokinematics Horizontal plane adjustments during scapulothoracic protraction Sagittal plane adjustment during scapulothoracic elevation
Clavicle • Acts a strut connecting upper extremity to thorax • Protects brachial plexus & vascular structures • Serves as attachment site for many shoulder muscles
Scapulothoracic Joint • No osseous connection • SUBSCAP & SA
Glenohumeral Joint: Humerus Retroversion angle: 30°
Glenohumeral Joint: Humerus Inclination angle: 45°
Glenohumeral Joint: Glenoid Fossa • Inclination angle: 5° • Retroversion angle: 7°
Glenohumeral Joint: Glenoid Fossa • Articular cartilage thicker on periphery • Shallow fossa 1/3 diameter of humeral head
Pure rotation Bony restraint poor Head 4-5X larger than fossa Close-packed position ABD with LR Glenohumeral Joint: Bony Structure
Glenohumeral Joint: Joint Capsule • Inherently lax • Surface area 2X head • Provides restraint for ABD, ADD, LR, MR
Glenohumeral Joint:Superior GH Ligament • Resists inferior translation in rest or adducted arm • Well-developed in 50%
Glenohumeral Joint: Coracohumeral Ligament • Resists inferior translation in shoulders with less-developed SGH
Glenohumeral Joint:Middle GH Ligament • Great variability in proximal attachment & morphology • Absent in 30% • Resists inferior translation in ABD & ER • Restrains anterior translation (45° ABD)
Glenohumeral Joint:Inferior GH Ligament • 3 components (A,P,Ax) • Resists inferior, anterior, & posterior translation
Glenohumeral Joint: Bursae • Subcoracoid • Subacromial • Subscapular
Glenohumeral Joint: Accessory Structures Labrum • 50% of depth • Increases tangential stability 20%
Glenohumeral Joint: Intra-articular Pressure • Synovial fluid causes adhesion • Provides ~50% restraint