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Unformatted text preview: Foundations of Occupation: Foundations Kinesiology Shoulder Complex – Part 2 Lecture 6 Summer 2010 Announcements Announcements Tests will be returned to you in labs for Tests your review ONLY. Please review missed questions and also Please the ones you got right! This will help you for your midterm on Friday. Try and get your questions asked/clarified Try in labs and/or office hours this week before Friday’s midterm before Overview Introduction: Motions of the Glenohumeral Joint Scapulohumeral Rhythm Muscles of the Glenohumeral Joint Functional and Clinical Considerations: The Rotator Cuff Shoulder Subluxation AROM and PROM of the Shoulder Motions of the Glenohumeral Joint Motions Flexion – sagittal plane around X axis, 0-180 degrees Extension – 0-60 degrees ABduction – frontal plane around Z axis, 0-180 degrees ADduction – return form AB External / Internal Rotation – horizontal plane around Y axis, 0-90 degrees Horizontal / AB Horizontal AD – horizontal plane around Y axis Begin at 90 degrees of shoulder flexion The Video The Scapulohumeral Rhythm Video Scapulohumeral Rhythm : Phase One Phase First 30 degrees of Scapulothoracic (ST) Motion - scapular upward rotation – occurs at: Sternoclavicular (SC) joint with 25 degrees of elevation of lateral end of clavicle Acromioclavicular (AC) joint with 5 degrees of upward rotation of the scapula Sequence: Serratus anterior and traps 2 and 4 initiate upward rotation of scapula, which elevates clavicle Acromioclavicular ligament is taut allowing for constant relationship between clavicle and scapula Lateral end of clavicle elevates 25 degrees Costoclavicular ligament becomes taut, limiting clavicular elevation Scapula upwardly rotates 5 degrees at AC joint until coracoclavicular ligament becomes taut Primary arc of motion has its axis at base of spine of scapula 30 degrees of ST motion is accompanied by 60 degrees of GH motion Arm raised to 90 -100 degrees Last 30 degrees of Scapulothoracic Motion - scapular upward rotation – occurs at: Acromioclavicular (AC) joint with 25 degrees of upward rotation of the scapula Sternoclavicular (SC) joint with 5 degrees of elevation of lateral end of clavicle Sequence: Scapular upward rotators continue to pull Coracoclavicular ligament becomes taut, causing rotation of clavicle, anterior border flips up and back, becoming superiorly positioned Clavicle and scapula now free to complete upward rotation (above) Scapula upwardly rotates the final 30 degrees Primary axis of rotation is at the acromioclavicular joint Raising arm from horizontal to vertical position involves an additional 30 degrees of scapular upward rotation AND 60 degrees of glenohumeral motion Scapulohumeral Rhythm : Phase Two Phase Scapulohumeral Rhythm Summarized Scapulohumeral
Phase One: Accepting 180 degrees as maximal range of flexion and aBduction of humerus, raising arm to horizontal involves 60 degrees of GH motion and 30 degrees of ST motion. Scapular motion is composed of 25 degrees clavicular elevation at SC jt, and 5 degrees upward rotation at the AC joint. Phase Two: Raising arm from horizontal to vertical involves an additional 60 degrees of GH motion and 30 degrees of scapular motion allowed by clavicular rotation composed of 5 degrees clavicular elevation at SC joint, and 25 degrees upward rotation at AC joint. Clinical Implications: Scapulohumeral Rhythm Shoulder cannot fully flex/aBd without Shoulder scapulothoracic (ST) motion! scapulothoracic Attempting ROM without movement at ST Attempting articulation will cause damage… articulation Damage @ SC ligament/joint -> clavicle cannot Damage elevate -> limited shoulder motion elevate Damage @ coracoclavicular ligament -> clavicle Damage will not rotate -> limited shoulder motion will Muscles of the Glenohumeral Joint Deltoids Location: Location: proximal attachments extend anteriorly from the proximal lateral 1/3 of the clavicle to acromion to border of spine of scapula spine distal attachment on deltoid tuberosity Much of the force of the deltoid causes an Much upward compression of the humerus against the acromion The action of the deltoid is very dependent upon The scapular rotation so that this compression is functional, preventing impingement of head of the humerus against its overlying structures. the Deltoids Deltoids Anterior deltoid prime mover for flexion / horizontal AD assists with AB / internal rotation Middle deltoid prime mover for AB / horizontal AB Posterior deltoid prime mover for horizontal AB assists with extension and external rotation Supraspinatus Supraspinatus Acts with deltoid as prime mover for Abduction Penniform fibers give power Stabilizer when carrying heavy loads IT Muscles: Infraspinatus and Teres Minor Infraspinatus Both have tendinous distal insertion in glenohumeral capsule near greater tubercle Prime movers for horizontal AB, external rotation Muscular reinforcement of joint capsule http://z.about.com/d/p/440/e/f/19622.jpg http://z.about.com/d/p/440/e/f/19622.jpg Subscapularis Subscapularis Fills the entire anterior surface of the scapula Prime mover for Internal rotation Stabilizes the glenohumeral joint due to its distal attachment Depresses head of humerus during AB and flexion Latissimus Dorsi and Teres Major Latissimus Lats are prime Lats movers for extension and AD, especially when arm is raised 30-90 degrees 30-90 Assists with horizontal Assists AB AB Acts in internal rotation rotation Teres Major is located Teres just below teres minor just “Little helper” of Little latissimus dorsi latissimus Prime mover for Prime extension and AD extension Prime mover for IR Assists with horizontal Assists AB AB Pectoralis Major Pectoralis Sternal portion - prime mover for AD and horizontal AD and prime mover for extension when arm begins in position of flexion Clavicular portion - lies close to anterior deltoid and is prime mover for flexion and horizontal AD Assists with IR and AB Coracobrachialis Coracobrachialis Line of pull is in front Line humerus humerus Prime mover for Prime horizontal AD and shoulder flexion shoulder Stabilizes shoulder Stabilizes when carrying a heavy load heavy Biceps (assist muscles) muscles) Primarily muscle of elbow, it can substitute for shoulder muscles in flexion, AD (short head), AB (long head), IR, and horizontal AD. When elbow is straight, both heads of the biceps are active during humeral flexion and AB if resistance is applied in these motions. When elbow is flexed - active insufficiency – with shoulder flexion Triceps (assist muscles) Triceps Primary muscle of Primary elbow for extension elbow Long head crosses Long over shoulder and inserts on scapula on infraglenoid tubercle infraglenoid Assists with extension Assists and ADduction of humerus S.I.T.S. Muscles: The Rotator Cuff The National Library of Medicine Putting it Together: Functional and Clinical Considerations
The Rotator Cuff Shoulder Subluxation AROM & PROM of the Shoulder: Scapulohumeral Rhythm Functional Considerations Functional of the Rotator Cuff of Stabilization of the glenohumeral joint Neutralizing synergies Downward pull to counteract upward pull of deltoids (example: supraspinatus – abducts humerus & deltoid abducts; infraspinatus, teres minor, & subscapularis – downward rotation & adduction Antagonist forces Internal and external rotation (example: subscapularis for internal rotation & infraspinatus & teres minor for external rotation) Shoulder Elevation and ABduction Shoulder Both supraspinatus and deltoids ABduct humerus Deltoids force is more linear due to short moment arm Early in ABduction: concentric contraction of Early deltoid primarily elevates humeral head deltoid 3 factors prevent an undesirable elevation factors (impingement): (impingement): Supraspinatus Infraspinatus, teres minor and subscapularis As abduction progresses -> line of pull of deltoid As changes changes Prevention of Downward Displacement of Humeral Head Displacement Biomechanical forces typically Biomechanical involved in stabilization of humeral head: head:
Biomechanical alignment – Biomechanical scapula/glenoid fossa scapula/glenoid Glenoid labrum Capsule and ligaments Supraspinatus Clinical Implications: Shoulder Subluxation Glenohumeral (Inferior) Subluxation = Glenohumeral downward displacement of humeral head downward Scapular mal-alignment as a primary Scapular “underlying problem.” “underlying Intervention includes: ...
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This note was uploaded on 09/02/2010 for the course OT 440 taught by Professor Rafeedie during the Fall '10 term at USC.
- Fall '10