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The Shoulder Complex. A.General Structure & Function B.Structure & Function of Specific Joints C.Muscular Considerations D.Specific Functional Considerations.

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Presentation on theme: "The Shoulder Complex. A.General Structure & Function B.Structure & Function of Specific Joints C.Muscular Considerations D.Specific Functional Considerations."— Presentation transcript:

1 The Shoulder Complex

2 A.General Structure & Function B.Structure & Function of Specific Joints C.Muscular Considerations D.Specific Functional Considerations E.Common Injuries

3 The Shoulder Complex A.General Structure & Function B.Structure & Function of Specific Joints C.Muscular Considerations D.Specific Functional Considerations E.Common Injuries

4 General Structure

5 General Function Provides very mobile, yet strong base for hand to perform its intricate gross and skilled functions Transmits loads from upper extremity to axial skeleton

6 Shoulder Girdle

7 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

8 Abduction/Lateral Tilt (Protraction) Adduction/Reduced Lateral Tilt (Retraction) Linear Movement Frontal Plane Angular movement Transverse Plane

9 Depression Elevation Linear Movement Frontal Plane

10 Downward rotation Upward rotation

11 Shoulder Complex Movements Upward tilt Reduction of Upward Tilt Angular movement Sagittal plane

12 Limited by capsular torsion Limited by bony impingement of greater tubercle on acromion

13

14 Large ROM Due To: Poor bony structure Poor ligamentous restraint Scapulohumeral cooperative action

15 The Shoulder Complex A.General Structure & Function B.Structure & Function of Specific Joints C.Muscular Considerations D.Specific Functional Considerations E.Common Injuries

16 Structure & Function of Specific Joints 1.Sternoclavicular Joint 2.Acromioclavicular Joint 3.Scapulothoracic Joint 4.Glenolhumeral Joint 5.Coracoacromial Arch

17 Sternoclavicular Joint: Bony Structure Poor Diarthrodial Biaxial

18 Sternoclavicular Joint: Capsule Very strong

19 Sternoclavicular Joint: Interclavicular Ligament Resists superior & anterior (posterior portion) motion

20 Sternoclavicular Joint: Sternoclavicular Ligament Resists anterior (PSL), posterior (ASL), & superior motion

21 Sternoclavicular Joint: Costoclavicular Ligament Resists upward and posterior motion

22 Sternoclavicular Joint: Accessory Structures Resists medial & inferior displacement via articular contact

23 Sternoclavicular Joint: Articular Surfaces Medial end of clavice is convex Clavicular facet is reciprocally shaped

24 Sternoclavicular Joint: Motions Axial Rotation:50° EL/DEP: 35° PROT/RET: 35°

25 Sternoclavicular Joint: Motions Frontal plane Elev/Dep Sagittal plane Post Rot Horizontal plane ProT/ReT Ant/Post axis Vertical axis

26 Acromioclavicular Joint Bony Structure Poor Diarthrodial Nonaxial

27 Acromioclavicular Joint: Joint Capsule Very weak

28 Acromioclavicular Joint Acromioclavicular Ligament Resists axial rotation & posterior motion

29 Acromioclavicular Joint Coracoclavicular Ligament Resists superior motion

30 Acromioclavicular Joint Accessory Structures Articular disc

31 Acromioclavicular Joint: Motion Little relative motion at AC joint UR/DR:60° EL/DEP: 30° PROT/RET: 30-50°

32 Acromioclavicular Joint: Osteokinematics Horizontal plane adjustments during scapulothoracic protraction Sagittal plane adjustment during scapulothoracic elevation

33 Clavicle Acts a strut connecting upper extremity to thorax Protects brachial plexus & vascular structures Serves as attachment site for many shoulder muscles

34 Scapula

35 Scapular Plane

36 Scapulothoracic Joint No osseous connection SUBSCAP & SA

37 Glenohumeral Joint: Humerus Retroversion angle: 30°

38 Glenohumeral Joint: Humerus Inclination angle: 45°

39 Glenohumeral Joint: Glenoid Fossa Inclination angle: 5° Retroversion angle: 7°

40 Glenohumeral Joint: Glenoid Fossa Articular cartilage thicker on periphery Shallow fossa 1/3 diameter of humeral head

41 Glenohumeral Joint: Bony Structure Pure rotation Bony restraint poor Head 4-5X larger than fossa Close-packed position ABD with LR

42 Glenohumeral Joint: Joint Capsule Inherently lax Surface area 2X head Provides restraint for ABD, ADD, LR, MR

43 Glenohumeral Joint: Superior GH Ligament Resists inferior translation in rest or adducted arm Well-developed in 50%

44 Glenohumeral Joint: Coracohumeral Ligament Resists inferior translation in shoulders with less- developed SGH

45 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)

46 Glenohumeral Joint: Inferior GH Ligament 3 components (A,P,Ax) Resists inferior, anterior, & posterior translation

47 Glenohumeral Joint: Bursae Subcoracoid Subacromial Subscapular

48 Glenohumeral Joint: Accessory Structures 50% of depth Increases tangential stability 20% Labrum

49 Glenohumeral Joint: Intra-articular Pressure Synovial fluid causes adhesion Provides ~50% restraint

50 Coracoacromial Arch

51 Glenohumeral Joint: ROM Flexion (167° W; 171° M) 30° in max LR Extension (60°) Abduction (180°) 60° in max IR Hyperadduction (75°)

52 Glenohumeral Joint: ROM Medial rotation (90°) Lateral rotation (90°) Horizontal abduction (45°) Horizontal adduction (135°) Total rotation 180° Total ROT 90° in 90° ABD Role of multiarticular muscles???

53 Glenohumeral Joint: ROM Medial rotation (90°) Lateral rotation (90°) Horizontal abduction (45°) Horizontal adduction (135°)

54 Soft Tissue Restraint Summary Anterior Capsule Labrum Glenohumeral lig Coracohumeral lig Subscapularis Pectoralis major Inferior Capsule Triceps brachii (L) Posterior Capsule Labrum Teres minor Infraspinatus Superior Labrum Coracohumeral lig Suprapinatus Biceps brachii (L) Coracoacromial arch Subacromial bursa

55 The Shoulder Complex A.General Structure & Function B.Structure & Function of Specific Joints C.Muscular Considerations D.Specific Functional Considerations E.Common Injuries

56 Shoulder girdle has its own set of muscles.

57 Retraction of the Scapulothoracic Joint Levator scapula

58 Protraction of the Scapulothoracic Joint Pectoralis minor

59 Pathomechanics of a weak serratus anterior muscle Deltoid force causes scapula to downwardly rotate. Unstable and cannot resist deltoid force

60

61

62 GH Flexion Prime flexors: Anterior deltoid Pectoralis major: clavicular portion Assistant flexors: Coracobrachialis Biceps brachii: short head

63 GH Flexion Anterior deltoid Coracobrachialis Biceps brachii

64 GH Extension Gravitational force Posterior deltoid Latissimus dorsi Pectoralis major (sternal) Teres major (with resistance)

65 Abduction at Glenohumeral Joint Major abductors of humerus: Supraspinatus Initiates abduction Active for first 110 degrees of abduction Middle deltoid Active 90-180 degrees of abduction Superior dislocating component neutralized by infraspinatus, subscapularis, and teres minor

66 Abduction at Glenohumeral Joint Initiates abduction Active for first 110 degrees of abduction Active 90-180 degrees of abduction Superior dislocating componentneutralized by infraspinatus, subscapularis, and teres minor

67 Abduction at Glenohumeral Joint: The Kinetic Arc

68 Adduction of Glenohumeral Joint Primary adductors: Latissimus dorsi Teres major Sternocostal pectoralis Minor assistance: Biceps brachii: short head Triceps brachii: long head Above 90 degrees- coracobrachialis and subscapularis

69 GH Medial Rotation Subscapularis Latissimus dorsi Pectoralis major Teres major (with resistance) Decreased activity with ABD

70 GH Lateral Rotation Primary Infraspinatus Assistant: Teres minor Posterior deltoid

71 Horizontal Adduction and Abduction Anterior to joint: Pectoralis major (both heads), anterior deltoid, coracobrachialis Assisted by short head of biceps brachi Posterior to joint: Middle and posterior deltoid, infraspinatus, teres minor Assisted by teres major, latissimus dorsi

72 Muscle Strength Adduction (2X ABD) Extension Flexion Abduction Internal rotation (max in neutral) External rotation (max at 90° FL) Role of multiarticular muscles???

73 The Shoulder Complex A.General Structure & Function B.Structure & Function of Specific Joints C.Muscular Considerations D.Specific Functional Considerations E.Common Injuries

74 Specific Functional Considerations Stability Functions of Shoulder Girdle Mobility Functions of Shoulder Girdle Rotator Cuff Function

75 Stability Functions of Shoulder Girdle Provides stable base from which shoulder muscles can generate force Shoulder girdle muscles as stabilizers Maintain appropriate force-length relationship Maintain maximum congruence of shoulder joint

76 Specific Functional Considerations Stability Functions of Shoulder Girdle Mobility Functions of Shoulder Girdle Rotator Cuff Function

77 Mobility Functions of Shoulder Girdle Permits largest ROM of any complex in the body Shoulder girdle increases ROM with less compromise of stability (scapulohumeral rhythm) (4 joints vs. 1 joint) Facilitate movements of the upper extremity by positioning GH favorably

78 Dynamic Stabilization Mechanisms Passive muscle tension Compressive forces from muscle contraction Joint motion that results in tightening of passive structures Redirection of joint force toward center of GH joint

79 Muscular Considerations Force-length relationships quite variable due to multiple joints Tension development in agonist frequently requires tension development in antagonist to prevent dislocation of the humeral head Force couple – 2 forces equal in magnitude but opposite in direction

80 Movements in the Frontal Plane GH Joint - Abduction Shoulder Girdle: UR Totals Upward rotation - 60° GH Abduction - 120° 2:1 (.66) ratio 1.25:1 after 30° 0.5-0.75 across individuals ABD 30° ABD - 30° UR - 40° ABD - 60° UR - 20°

81 Movements in the Frontal Plane GH Joint - Adduction Shoulder Girdle: DR Fig 5.17

82 Movements in the Sagittal Plane GH Joint – Flexion & Extension Shoulder Girdle: UR ELEV (>90°) PROT ( to 90°) RET (>90°) Fig 5.18

83 Movements in the Sagittal Plane GH Joint - Hyperextension Shoulder Girdle: Upward tilt of scapula Fig 5.20

84 Movements in the Transverse Plane GH Joint – MR & LR Fig 5.22a

85 Spinal Contribution to GH Motion

86 Movements in the Transverse Plane GH HAdd & HAbd

87 Influences on GH ROM Humeral position in other planes FL limited by ER (30 FL in max ER) ABD limited by IR (60 -90 ABD in max IR) ABD with ER = 90-120 Rotation limited by ABD (total ROT only 90 in 90 ABD) Scapular position Elbow position

88 Large ROM Due To: Poor bony structure Poor ligamentous restraint Scapulohumeral coordination Normal movement dependent on interrelationships of 4 joints Restriction in any of these four can impair normal function

89 Specific Functional Considerations Stability Functions of Shoulder Girdle Mobility Functions of Shoulder Girdle Rotator Cuff Function

90 Subscapularis Teres minor Supraspinatus Infraspinatus

91

92 Function of Rotator Cuff Large external muscles (e.g., lats, delts) create shear forces Rotator cuff provides Joint compression Tangential restraint (Ant, Post, Sup)

93 Destabilizing Action of Deltoid

94 Deltoid produces superior shear force at GH joint.

95 Subscapularis Resists superior shear Produces simultaneous internal rotation

96 Infraspinatus & Teres Minor Resists superior shear Neutralizes SUBSCAP internal rotation

97 Supraspinatus

98 Summary of Active Arthrokinematics Resisting Shear

99 Destabilizing Action of Latissimus Dorsi LD pulls humerus INF SSP resists INF force INF & SUBSCAP create compressive force

100 The Shoulder Complex A.General Structure & Function B.Structure & Function of Specific Joints C.Muscular Considerations D.Specific Functional Considerations E.Common Injuries

101 Common Shoulder Injuries Joint dislocations Clavicular fracture Rotator cuff injuries Other rotational injuries Subscapular neuropathy

102 Evaluation of Injuries Mechanism of Injury (MOI): How did the injury occur? Pathology (PATH): What tissues are damaged? Sign & Symptoms (S&S): What does the patient tell you? What can be determined from an evaluation of the injury?

103 Joint Dislocations: Acromioclavicular Sprain AKA Shoulder Separation MOI: Downward blow to outer end of shoulder Fall on outstretched hand, Punching PATH: Sprain of AC ligaments S&S: Pain over AC joint Laxity of AC joint???

104 Joint Dislocations: Shoulder Dislocation MOI: Arm forcefully ABD & LR May occur by a blow to top of shoulder PATH: Head of humerus is forced out of the glenoid fossa S&S: Arm held out from side in slight ABD & LR Loss of normal rounded contour of deltoid muscle

105 Chronic Dislocation of the Shoulder MOI: Congenital abnormality Repeated acute dislocations PATH: Head of humerus relatively easily come out of the glenoid fossa Tissue damage due to repeated dislocations S&S: Usually not very painful

106 Clavicular Fracture MOI: Downward blow to outer end of shoulder Fall on outstretched hand PATH: Fracture to middle 1/3 S&S: Patient supports injured arm Head may be tilted toward injured side with face turned to opposite side

107 Rotator Cuff Injuries MOI: Overuse Falling on an outstretched hand PATH: Strains or tearing of rotator cuff muscles Supraspinatus most often injured S&S: Pain, Inflammation, Weakness

108 Impingement Possible mechanisms Weak or inflexible rotator cuff Small anatomical space Hyperabduction of GH joint GH ABD + ROT

109 Impingement: Roll-Slide Kinematics Roll created by abduction not countered with Slide action

110 Rotator Cuff Injury Anatomical cause of rotator cuff injury Kinesiological cause of injury

111 Impingement Narrow space Inextensibility of capsule, ligaments, muscles – esp. rotator cuff Abduction and internal/external rotations

112 During ABD SSP tendon pushed into acromion process & CA ligament During ROT SSP tendon dragged along the inferior surface of the acromion process

113 Rotator Cuff Injury Anatomical cause of rotator cuff injury Kinesiological cause of injury

114 Wind-Up Phase Kinesiological breakdown of overhand throwing First MotionMaximum knee lift of leg

115 Shoulder ABD (DELT & SSP) RC maintain proper humeral head position Kinesiological breakdown of overhand throwing Stride Lead leg begins to move Arms separate Lead foot contacts the ground

116 ER in ABD position; ER 150-180° ECC action of SUBSCAP (decelerates ER humerus) RC stabilization Kinesiological breakdown of overhand throwing Arm Cocking Lead foot contactMaximum shoulder external rotation

117 Concentric IR (PMJR & LD ) IR velocity (> 1000 °/s) RC stabilization Kinesiological breakdown of overhand throwing Arm Acceleration Maximum shoulder ERBall release

118 Decelerating IR & ADD ECC action of TMin RC stabilization Kinesiological breakdown of overhand throwing Arm Deceleration Ball releaseMaximum shoulder IR

119 Decelerating IR ECC action of TMin RC stabilization Kinesiological breakdown of overhand throwing Follow Through Maximum shoulder IREnds in balanced position

120 Rotator Cuff Injuries: Solution Alter technique during problem phases to avoid impingement Arm cocking Arm acceleration Strengthen rotator cuff Surgical repair Video techniques

121 Risk Factors Risk factor – a characteristic that influences the loading on the musculoskeletal system Movement risk factors – characteristics of a movement Intrinsic risk factors – the personal, physical, and psychological characteristics of an individual Extrinsic risk factors – the environmental and administrative procedures

122 Intrinsic Risk Factors Age and gender Physical fitness Overtraining Skeletal abnormalities Technique Warm-up Psychological factors

123 Technique Technique refers to the movement pattern of an individual during a particular movement or sequence of movements. Good technique is a movement pattern not only effective in performance, but also one that minimizes risk of injury by appropriately distributing the overall load throughout the kinetic chain. Poor technique is characterized by inappropriate utilization and summation of muscular effort and abnormal joint movements, both of which result in localized overload and, therefore, increased risk of injury.

124 Swimming Mechanism: ABD + IR Solutions: Lead with hand to IR Increase body roll to ABD

125 Supraspinatus Tear

126 Other Rotational Injuries Tears of labrum Mostly in anterior-superior region Tears of biceps brachii tendon Due to forceful rotational movements Also: calcification of soft tissues, degenerative changes in articular surfaces, bursitis

127 Biceps Tendon Tear

128 Subscapular Neuropathy Denervation of INF with strength GH ER Mechanism: Repeated stretching of nerve

129 Loads on the Shoulder Arm segment moment arm: Perpendicular distance between weight vector and shoulder. With elbow flexion, upper arm and forearm/hand segments must be analyzed separately. Large torques from extended moment arms countered by shoulder muscles. Load reduced by half with maximal elbow flexion

130 Injury Potential in the Shoulder Complex - Impacts Sternoclavicular Joint not commonly injured may sprain anteriorly if fall on top of shoulder or middle delt - pain in horizontal abd children may dislocate anteriorly during throwing because of increased joint mobility as compared to adults posterior dislocation may occur when force is applied to sternal end of clavicle; serious because of trachea, esophagus, and blood vessels located posteriorly Clavicular Injuries fx to any part due to direct trauma fx to middle 1/3 can occur by falling on shoulder, outstretched arm, or direct trauma to shoulder that transmits force down shaft of clavicle AC Injuries dislocation from fall on shoulder, fall on elbow or outstretched arm overuse injuries from overhand pattern (throwing, tennis, swimming) or sports that repeatedly load in the overhead position (wrestling, wt lifting)

131 Glenohumeral Injuries Most common dislocation in anterior (anterior-inferior 95%) most commonly dislocated when abducted and ER overhead recurrence rate 33- 50% (66-90% <20 yrs)


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