© McGraw-Hill Higher Education. All rights reserved. 5-1 Chapter 5 The Shoulder Joint

© McGraw-Hill Higher Education. All rights © McGraw-Hill Higher Education. All rights reserved. reserved. 5-5-11

Chapter 5 Chapter 5 The Shoulder JointThe Shoulder Joint

http://www.youtube.com/watch?v=0nNPZf6gOIchttp://www.youtube.com/watch?v=0nNPZf6gOIc

http://www.youtube.com/watch?v=gJNToClloZohttp://www.youtube.com/watch?v=gJNToClloZo

http://www.youtube.com/watch?v=HULJU_ROdCIhttp://www.youtube.com/watch?v=HULJU_ROdCI

http://www.youtube.com/watch?v=0nNPZf6gOIc

http://www.youtube.com/watch?v=gJNToClloZo

http://www.youtube.com/watch?v=HULJU_ROdCI


The Shoulder JointThe Shoulder Joint

• Shoulder joint is attached to axial skeleton Shoulder joint is attached to axial skeleton via the clavicle at SC jointvia the clavicle at SC joint

• Scapula movement usually occurs with Scapula movement usually occurs with movement of humerusmovement of humerus– Humeral flexion & abduction require scapula Humeral flexion & abduction require scapula

elevation, rotation upward, & abductionelevation, rotation upward, & abduction– Humeral adduction & extension results in Humeral adduction & extension results in

scapula depression, rotation downward, & scapula depression, rotation downward, & adductionadduction

– Scapula abduction occurs with humeral Scapula abduction occurs with humeral internal rotation & horizontal adductioninternal rotation & horizontal adduction

– Scapula adduction occurs with humeral Scapula adduction occurs with humeral external rotation & horizontal abductionexternal rotation & horizontal abduction


The Shoulder JointThe Shoulder Joint

• Wide range of motion of the shoulder Wide range of motion of the shoulder joint in many different planes requires a joint in many different planes requires a significant amount of laxitysignificant amount of laxity

• Common to have instability problemsCommon to have instability problems– Rotator cuff impingementRotator cuff impingement– Subluxations & dislocationsSubluxations & dislocations

• The price of mobility is reduced stabilityThe price of mobility is reduced stability• The more mobile a joint is, the less The more mobile a joint is, the less

stable it is & the more stable it is, the stable it is & the more stable it is, the less mobileless mobile


BonesBones

• Scapula, clavicle, & humerus serve as Scapula, clavicle, & humerus serve as attachments for shoulder joint musclesattachments for shoulder joint muscles– Scapular landmarksScapular landmarks

• supraspinatus fossasupraspinatus fossa• infraspinatus fossainfraspinatus fossa• subscapular fossasubscapular fossa• spine of the scapulaspine of the scapula• glenoid cavityglenoid cavity• coracoid processcoracoid process• acromion processacromion process• inferior angleinferior angle

From Seeley RR, Stephens TD, Tate P: Anatomy and physiology, ed 7, New York, 2006, McGraw-Hill


BonesBones

• Scapula, clavicle, & humerus serve Scapula, clavicle, & humerus serve as attachments for shoulder joint as attachments for shoulder joint musclesmuscles– Humeral landmarksHumeral landmarks

• HeadHead• Greater tubercleGreater tubercle• Lesser tubercleLesser tubercle• Intertubercular grooveIntertubercular groove• Deltoid tuberosityDeltoid tuberosity


BonesBones

• Key bony landmarksKey bony landmarks– Acromion processAcromion process– Glenoid fossaGlenoid fossa– Lateral borderLateral border– Inferior angleInferior angle– Medial borderMedial border– Superior angleSuperior angle– Spine of the scapula Spine of the scapula


Glenohumeral JointGlenohumeral Joint

• multiaxial ball-multiaxial ball-&-socket&-socket

• enarthrodialenarthrodial



– Glenoid labrum Glenoid labrum slightly slightly enhances enhances stability stability



– Glenohumeral Glenohumeral ligaments provide ligaments provide stabilitystability• especially especially

anteriorly & anteriorly & inferiorlyinferiorly

• inferior inferior glenohumeral glenohumeral ligament ligament












– Ligaments are quite lax until extreme Ligaments are quite lax until extreme ranges of motion reached due to wide ranges of motion reached due to wide range of motion involvedrange of motion involved

– Stability is sacrificed to gain mobilityStability is sacrificed to gain mobility



• Determining Determining exact range of exact range of each each movement is movement is difficult due to difficult due to accompanying accompanying shoulder girdle shoulder girdle movementmovement



– 90 to 95 degrees 90 to 95 degrees abductionabduction

– 0 degrees adduction, 0 degrees adduction, 75 degrees anterior 75 degrees anterior to trunkto trunk



– 40 to 60 degrees of 40 to 60 degrees of extensionextension

– 90 to 100 degrees of 90 to 100 degrees of flexionflexion



– 70 to 90 degrees of internal & external 70 to 90 degrees of internal & external rotationrotation



– 45 degrees of 45 degrees of horizontal horizontal abductionabduction

– 135 degrees of 135 degrees of horizontal horizontal adductionadduction



• Frequently injured due to anatomical designFrequently injured due to anatomical design– shallowness of glenoid fossashallowness of glenoid fossa– laxity of ligamentous structureslaxity of ligamentous structures– lack of strength & endurance in muscleslack of strength & endurance in muscles– anterior or anteroinferior glenohumeral anterior or anteroinferior glenohumeral

subluxations & dislocations – commonsubluxations & dislocations – common– posterior dislocations – rareposterior dislocations – rare– posterior instability problems somewhat posterior instability problems somewhat

commoncommon



• Rotator cuff is frequently injuredRotator cuff is frequently injured– Subscapularis, supraspinatus, infraspinatus, & Subscapularis, supraspinatus, infraspinatus, &

teres minor muscles teres minor muscles – attach to the front, top, & rear of humeral headattach to the front, top, & rear of humeral head– point of insertion enables humeral rotationpoint of insertion enables humeral rotation– vital in maintaining humeral head in correct vital in maintaining humeral head in correct

approximation within glenoid fossa while more approximation within glenoid fossa while more powerful muscles move humerus through its wide powerful muscles move humerus through its wide range of motion range of motion


Pairing of shoulder girdle & Pairing of shoulder girdle & shoulder joint movementsshoulder joint movementsShoulder jointShoulder joint Shoulder girdleShoulder girdle

AbductionAbduction Upward rotationUpward rotation

AdductionAdduction Downward rotationDownward rotation

FlexionFlexion Elevation/upward rotationElevation/upward rotation

ExtensionExtension Depression/downward rotationDepression/downward rotation

Internal rotationInternal rotation Abduction (protraction)Abduction (protraction)

External rotationExternal rotation Adduction (retraction)Adduction (retraction)

Horizontal abductionHorizontal abduction Adduction (retraction)Adduction (retraction)

Horizontal adductionHorizontal adduction Abduction (protraction)Abduction (protraction)


MovementsMovements

• AbductionAbduction– upward lateral upward lateral

movement of humerus movement of humerus out to the side, away out to the side, away from bodyfrom body

• AdductionAdduction– downward movement downward movement

of humerus medially of humerus medially toward body from toward body from abductionabduction


MovementsMovements

• FlexionFlexion– movement movement

of humerus of humerus straight straight anteriorlyanteriorly

• ExtensionExtension– movement movement

of humerus of humerus straight straight posteriorlyposteriorly


MovementsMovements

• Horizontal adduction Horizontal adduction (transverse flexion)(transverse flexion)– movement of humerus in a movement of humerus in a

horizontal or transverse horizontal or transverse plane toward & across chestplane toward & across chest

• Horizontal abduction Horizontal abduction (transverse extension)(transverse extension)– movement of humerus in a movement of humerus in a

horizontal or transverse horizontal or transverse plane away from chestplane away from chest


MovementsMovements

• External rotationExternal rotation– movement of movement of

humerus laterally humerus laterally around its long axis around its long axis away from midlineaway from midline

• Internal rotationInternal rotation– movement of movement of

humerus medially humerus medially around its long axis around its long axis toward midlinetoward midline


MovementsMovements

• Diagonal abductionDiagonal abduction– movement of humerus movement of humerus

in a diagonal plane in a diagonal plane away from midline of away from midline of bodybody

• Diagonal adductionDiagonal adduction– movement of humerus movement of humerus

in a diagonal plane in a diagonal plane toward midline of bodytoward midline of body


MusclesMuscles

• Intrinsic glenohumeral musclesIntrinsic glenohumeral muscles– Originate on scapula & clavicle Originate on scapula & clavicle – Deltoid, Coracobrachialis, Teres majorDeltoid, Coracobrachialis, Teres major– Rotator cuff groupRotator cuff group

• subscapularis, supraspinatus, infraspinatus, & subscapularis, supraspinatus, infraspinatus, & teres minorteres minor

• Extrinsic glenohumeral musclesExtrinsic glenohumeral muscles– latissimus dorsi & pectoralis majorlatissimus dorsi & pectoralis major


MusclesMuscles

• AnteriorAnterior– Pectoralis majorPectoralis major– CoracobrachialisCoracobrachialis– SubscapularisSubscapularis

• SuperiorSuperior– DeltoidDeltoid– SupraspinatusSupraspinatus

From Shier D, Butler J, Lewis R: Hole’s essentials of human anatomy and physiology, ed 9, New York, 2006, McGraw-Hill.


MusclesMuscles

• SuperiorSuperior– DeltoidDeltoid– SupraspinatusSupraspinatus

• PosteriorPosterior– Latissimus dorsiLatissimus dorsi– Teres majorTeres major– InfraspinatusInfraspinatus– Teres minorTeres minor

From Shier D, Butler J, Lewis R: Hole’s essentials of human anatomy and physiology, ed 9, New York, 2006, McGraw-Hill.


Deltoid MuscleDeltoid Muscle

Anterior fibers: Anterior fibers: abduction, flexion, abduction, flexion, horizontal adduction, horizontal adduction, & internal rotation& internal rotation

Middle fibers: Middle fibers: abductionabduction

Posterior fibers: Posterior fibers: abduction, extension, abduction, extension, horizontal abduction, horizontal abduction, & external rotation& external rotation


Pectoralis Major MusclePectoralis Major MuscleUpper fibers (clavicular head): internal Upper fibers (clavicular head): internal

rotation, horizontal adduction, rotation, horizontal adduction, flexion, abduction (once arm is flexion, abduction (once arm is abducted 90 degrees, upper fibers abducted 90 degrees, upper fibers assist in further abduction), & assist in further abduction), & adduction (with arm below 90 adduction (with arm below 90 degrees of abduction)degrees of abduction)

Lower fibers (sternal Lower fibers (sternal head): internal head): internal rotation, horizontal rotation, horizontal adduction, extension, adduction, extension, & adduction& adduction


Latissimus Dorsi MuscleLatissimus Dorsi Muscle

AdductionAdduction

ExtensionExtension

Internal rotationInternal rotation

Horizontal abductionHorizontal abduction


Coracobrachialis MuscleCoracobrachialis Muscle

FlexionFlexion

AdductionAdduction

Horizontal adductionHorizontal adduction


Rotator cuff musclesRotator cuff muscles• SSupraspinatusupraspinatus

– attach to greater tubercle from above (Abduct)attach to greater tubercle from above (Abduct)

• IInfraspinatusnfraspinatus– attach to greater tubercle posteriorly (Ext. Rot.)attach to greater tubercle posteriorly (Ext. Rot.)

• TTeres Minoreres Minor– attach to greater attach to greater

tubercle posteriorly tubercle posteriorly (Ext. Rot.)(Ext. Rot.)

• SSubscapularisubscapularis– attach to lesser attach to lesser

tubercle anterior (Int. tubercle anterior (Int. Rot.)Rot.)


Rotator cuff musclesRotator cuff muscles

• not very largenot very large• must possess strength & muscular endurancemust possess strength & muscular endurance• conducting repetitious overhead activities conducting repetitious overhead activities

(throwing, swimming, & pitching) with poor (throwing, swimming, & pitching) with poor technique, muscle fatigue, or inadequate warm-technique, muscle fatigue, or inadequate warm-up & conditioning leads to failure of rotator cuff up & conditioning leads to failure of rotator cuff muscle group in dynamically stabilizing humeral muscle group in dynamically stabilizing humeral head in glenoid cavityhead in glenoid cavity

• leads to further rotator cuff problems such as leads to further rotator cuff problems such as tendinitis & rotator cuff impingement within tendinitis & rotator cuff impingement within subacromial space subacromial space


Subscapularis MuscleSubscapularis Muscle

AdductionAdduction

ExtensionExtension

Stabilization of the Stabilization of the humeral head in humeral head in glenoid fossaglenoid fossa



Supraspinatus MuscleSupraspinatus Muscle

AbductionAbduction

Stabilization of the Stabilization of the humeral head in humeral head in glenoid fossaglenoid fossa


InfraspinatusInfraspinatus Muscle Muscle

External rotationExternal rotation


ExtensionExtension

Stabilization of humeral Stabilization of humeral head in the glenoid fossahead in the glenoid fossa


Teres Minor MuscleTeres Minor Muscle

External rotationExternal rotation


ExtensionExtension

Stabilization of humeral Stabilization of humeral head in the glenoid fossahead in the glenoid fossa


Teres Major MuscleTeres Major Muscle

Extension, particularly from Extension, particularly from the flexed position to the the flexed position to the posteriorly extended posteriorly extended positionposition


Adduction, particularly from Adduction, particularly from the abducted position the abducted position down to the side & down to the side & toward midline of body toward midline of body


Glenohumeral FlexionGlenohumeral Flexion

• AgonistsAgonists– Anterior DeltoidAnterior Deltoid– Upper Pectoralis MajorUpper Pectoralis Major


Glenohumeral ExtensionGlenohumeral Extension

• AgonistsAgonists– Teres Teres

MajorMajor– Latissimus Latissimus

DorsiDorsi– Lower Lower

Pectoralis Pectoralis MajorMajor


Glenohumeral AbductionGlenohumeral Abduction

• AgonistsAgonists– DeltoidDeltoid– SupraspinatusSupraspinatus– Upper Pectoralis Upper Pectoralis

MajorMajor


Glenohumeral AdductionGlenohumeral Adduction

• EX. Lat. Pull - EX. Lat. Pull - pull down pull down weightsweights

• AgonistsAgonists– Latissimus Latissimus

DorsiDorsi– Teres MajorTeres Major– Lower Lower

Pectoralis Pectoralis MajorMajor


Glenohumeral Internal RotationGlenohumeral Internal Rotation

• AgonistsAgonists– Latissimus Latissimus

DorsiDorsi– Teres MajorTeres Major– SubscapularisSubscapularis– Pectoralis Pectoralis

MajorMajor

• All attach All attach anteromedially anteromedially on humeruson humerus


Glenohumeral External RotationGlenohumeral External Rotation

• AgonistsAgonists– InfraspinatusInfraspinatus– Teres MinorTeres Minor

• Both attach Both attach posteriorly on posteriorly on greater tuberclegreater tubercle


Glenohumeral Horizontal Glenohumeral Horizontal AbductionAbduction

• AgonistsAgonists– Posterior Posterior

DeltoidDeltoid– Middle Middle

DeltoidDeltoid– Infraspinatus Infraspinatus – Teres MinorTeres Minor


Glenohumeral Horizontal Glenohumeral Horizontal AdductionAdduction

• AgonistsAgonists– Anterior DeltoidAnterior Deltoid– Pectoralis MajorPectoralis Major– CoracobrachialisCoracobrachialis


Glenohumeral Diagonal Glenohumeral Diagonal AbductionAbduction

• AgonistsAgonists– Posterior DeltoidPosterior Deltoid– InfraspinatusInfraspinatus– Teres MinorTeres Minor– Triceps Brachii Triceps Brachii

(Long Head)(Long Head)


Glenohumeral Diagonal Glenohumeral Diagonal AdductionAdduction

• Agonists - both Agonists - both low & highlow & high– Anterior DeltoidAnterior Deltoid– CoracobrachialisCoracobrachialis– Biceps Brachii Biceps Brachii

(short head)(short head)– Pectoralis Major - Pectoralis Major -

Upper & LowerUpper & Lower


NervesNerves

• All shoulder joint muscles are innervated from All shoulder joint muscles are innervated from the brachial plexusthe brachial plexus

• Lateral pectoral nerve arising from C5, C6, & Lateral pectoral nerve arising from C5, C6, & C7C7– Pectoralis major (clavicular head)Pectoralis major (clavicular head)

• Medial pectoral nerve arising from C8 & T1Medial pectoral nerve arising from C8 & T1– Pectoralis major (sternal head)Pectoralis major (sternal head)

• Thoracodorsal nerve arising from C6, C7, & Thoracodorsal nerve arising from C6, C7, & C8C8– Latissimus dorsiLatissimus dorsi


NervesNerves

• Axillary nerve branching Axillary nerve branching from C5 & C6from C5 & C6– DeltoidDeltoid– Teres minorTeres minor– Sensation to lateral patch of Sensation to lateral patch of

skin over deltoid region of skin over deltoid region of armarm

• Upper subscapular nerves Upper subscapular nerves arising from C5 & C6arising from C5 & C6– SubscapularisSubscapularis


NervesNerves

• Lower subscapular nerve arising from Lower subscapular nerve arising from C5 & C6C5 & C6– SubscapularisSubscapularis– Teres majorTeres major

• Suprascapula nerve originating from Suprascapula nerve originating from C5 & C6C5 & C6– SupraspinatusSupraspinatus– InfraspinatusInfraspinatus


NervesNerves

• Musculotaneous nerve Musculotaneous nerve branching from C5, C6, & branching from C5, C6, & C7C7– CoracobrachialisCoracobrachialis– Sensation to radial aspect Sensation to radial aspect

of forearm of forearm

Documents

© McGraw-Hill Higher Education. All rights reserved. 5-1 Chapter 5 The Shoulder Joint