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THE SHOULDER GIRDLE

THE SHOULDER GIRDLEDanielle G. Devilleres, PTRP

Major componentsBony segmentsClavicleScapula HumerusThe articular segments of the shoulder complex are designed primarily for mobilityStability is provided by the muscles and therefore called, dynamic stability

THE JOINTS Sternoclavicular jointOnly structural attachment of the shoulder complex and upper extremity to the axial skeletonPlane synovial jointSynovial joint capsulePresence of a joint disc3 rotatory and translatory degrees of freedom3 major ligaments

THE JOINTS Sternoclavicular jointARTICULAR SURFACESConsist of 2 shallow saddle-shaped surfaces(1) medial end of the clavicle(2) notch formed by the manubrium of sternum and 1st costal cartilage

THE JOINTS Sternoclavicular joint* insert picture hereFig 7-2A

THE JOINTS Sternoclavicular jointARTICULAR SURFACESBoth surfaces are incongruentSuperior portion of medial clavicle does not contact the manubrium at all but serves as attachement for sternoclavicular disc and interclavicular ligament

THE JOINTS Sternoclavicular joint* insert picture hereFig 7-2A

THE JOINTS Sternoclavicular jointSTERNOCLAVICULAR DISCFibrocartilage disc or meniscusIncreases the congruency between the articulating surfacesUpper portion is attached to posterosuperior clavicleLower portion is attached to manubrium and 1st costal cartilage as well as to the anterior and posterior aspect of fibrous SC capsule

THE JOINTS Sternoclavicular joint* insert picture hereFig 7-3

THE JOINTS Sternoclavicular jointSTERNOCLAVICULAR DISCTransects the SC joint space diagonally dividing the joint into 2 separate cavitiesActs like a hinge of pivot joint for the medial end of clavicle during shoulder motionProvides stability = increasing jt. Congruence and by absorbing forces transmitted along the clavicle

THE JOINTS Sternoclavicular joint* insert picture hereFig 7-3

THE JOINTS Sternoclavicular jointSTERNOCLAVICULAR DISCDuring elevation and depression of clavicleMedial end of clavicle rolls and glides on the SC discUpper attachment of disc serves as the pivot point

During protraction and retraction of clavicleSC disc and medial end of clavicle roll and slide together on the manubrial facetLower attachment of disc serves as the pivot point

THE JOINTS Sternoclavicular jointSTERNOCLAVICULAR DISCTherefore, the SC disc is considered part of the manubrium during elevation and depressionSC disc is considered part of the clavicle during protraction and retraction

THE JOINTS Sternoclavicular jointSTERNOCLAVICULAR JOINT CAPSULE AND LIGAMENTSFairly strong fibrous capsulePosterior capsule provides the primary restraint to both anterior and posterior translations of the medial clavicle on the sternum

THE JOINTS Sternoclavicular jointSTERNOCLAVICULAR JOINT CAPSULE AND LIGAMENTSBut majorly depends on 3 ligament complexes for supportAnterior and posterior SC ligamentsReinforce the capsuleCheck anterior and posterior translatory movement of the medial end of clavicle

THE JOINTS Sternoclavicular joint* insert picture hereFig 7-4

THE JOINTS Sternoclavicular jointSTERNOCLAVICULAR JOINT CAPSULE AND LIGAMENTSBut majorly depends on 3 ligament complexes for supportCostoclavicular ligamentVery strong ligament between clavicle and the first ribHas 2 segments or laminaeAnterior lamina fibers directed laterally from the 1st rib to the claviclePosterior lamina fibers directed medially from the 1st rib to the clavicle

THE JOINTS Sternoclavicular joint* insert picture hereFig 7-4

THE JOINTS Sternoclavicular jointSTERNOCLAVICULAR JOINT CAPSULE AND LIGAMENTSBut majorly depends on 3 ligament complexes for supportCostoclavicular ligamentBoth laminae limit elevation of the lateral end of the clavicle and, when taut, may contribute to the inferior gliding of the medial clavicle during elevationAlso limits the superiorly directed forces applied to the clavicle by the SCM and sternohyoid muscles

THE JOINTS Sternoclavicular jointSTERNOCLAVICULAR JOINT CAPSULE AND LIGAMENTSBut majorly depends on 3 ligament complexes for supportCostoclavicular ligamentPosterior lamina resist medial movement of the clavicle, absorbing some of the force that would be imposed on the SC disc

THE JOINTS Sternoclavicular joint* insert picture hereFig 7-4

THE JOINTS Sternoclavicular joint* insert picture hereFig 7-5

THE JOINTS Sternoclavicular jointSTERNOCLAVICULAR JOINT CAPSULE AND LIGAMENTSBut majorly depends on 3 ligament complexes for supportInterclavicular ligamentLimits excessive depression of the distal clavicle and superior gliding of medial clavicle on the manubriumLimitation of clavicular depression is critical to protect the brachial plexus and subclavian artery, which pass under the clavicle and over the 1st rib

THE JOINTS Sternoclavicular joint* insert picture hereFig 7-4

THE JOINTS Sternoclavicular joint* insert picture hereFig 7-2A

THE JOINTS Sternoclavicular jointSTERNOCLAVICULAR MOTIONS3 rotatory degrees of freedomElevation/depressionProtraction/retractionAnterior/posterior rotation

THE JOINTS Sternoclavicular jointSTERNOCLAVICULAR MOTIONSElevation/depressionAP axisElevation = lateral end of clavicle rotates upwardDepression = lateral end of clavicle rotates downwardConvex surface of clavicle must slide inferiorly on the concave manubrium and 1st costal cartilage during elevationAvailable range of SC elevation = 48 degreesAvailable range of SC depression = 15 degrees

THE JOINTS Sternoclavicular joint* insert picture hereFig 7-5

THE JOINTS Sternoclavicular jointSTERNOCLAVICULAR MOTIONSProtraction/retractionVertical axisProtraction = lateral clavicle moves anteriorlyRetraction = lateral clavicle moves posteriorlyConcave surface of clavicle