QUEEN MARY UNIVERSITY LONDON COURSES, Essays (high school) of Art

Download QUEEN MARY UNIVERSITY LONDON COURSES and more Essays (high school) Art in PDF only on Docsity! Anatomy & Biomechanics of the Shoulder www.fisiokinesiterapia.biz Shoulder Motion • Flexion - 150 - 1800 • Extension - 50 - 600 • Abduction - 150 - 1800 • External rotation - 900 • Internal rotation - 70 - 900 • Horizontal abduction • Horizontal adduction Combined Movements: Glenohumeral Motion • Bony geometry • Labrum • Capsuloligamen tous structures • Negative intra- articular pressure Passive Restraints: Capsuloligamentous Structures • SGHL • MGHL • IGHL complex • anterior band • posterior band • axillary pouch Glenohumeral ligaments: Superior glenohumeral ligament Middle glenohumeral Greater : ligament, ity Articular ‘ = f % margin ost, SS “Pe J ; : ° NY H aS j 10,9,7,6,2 paseo 1317) {| 85,4 Restraints to Internal Rotation • 00 - posterior band IGHLC • 450 - anterior & posterior band IGHLC • 900 - anterior & posterior band IGHLC Dependent on arm position: Restraints to Inferior Translation • 00 - SGHL & C-H • 900 - IGHLC Dependent on arm position: Glenohumeral Motion • Flexion/extension - 1200 • Abduction/adduction - 1200 • External/internal rotation • Horizontal abduction/ adduction Scapular Plane: Glenohumeral Motion • Abduction • Flexion • Extension • External rotation • Internal rotation Arthrokinematics: Control Capsule Control E E z 6 - < al a z < ac Fr -100 -80 -60 -40 -20 0 20 40 60 80 100 120 FLEXION ANGLE (degrees) Tight capsule Vented capsule Intact capsule E E z 2 < a 2 < c = Control 20 40 60 80 100 FLEXION ANGLE (degrees) Harryman et. al. 1990 Glenohumeral Motion •Combines rotation & translation to keep humeral head centered on glenoid Normal Arthrokinematics: Scapulohumeral Muscles • Deltoid • Pectoralis major • Latissimus dorsi • Teres major • Biceps • Coracobrachialis • Triceps Prime Movers: Scapulohumeral Muscles • Subscapularis • Supraspinatus • Infraspinatus • Teres Minor Rotator Cuff: Infraspinatus/Teres Minor • Reduces strain on anterior band of IGHLC • “Hamstrings” of glenohumeral joint Cain et. al. AJSM 1987 Long Head of Biceps • Biceps tendon force increases torsional rigidity to ER • No effect on strain of IGHLC • Effect lost with SLAP lesion Rodosky et. al. AJSM 1994 Biceps Becomes More Important Anterior Stabilizer as Capsuloligamentous Stability Decreases Itoi et. al. JBJS 1994 & Glousman et. al. 1988 Rotator Cuff Tear • Essential force couples disrupted • Weakness with external rotation • Little active elevation possible Supraspinatus/Posterior Cuff: Rotator Cuff Tear • Essential force couples disrupted • Weakness with internal & external rotation • Little active elevation possible Massive Tear : Subacromial Space Subacromial Space • Primary impingement: • structural stenosis of subacromial space • Secondary impingement: • functional stenosis of subacromial space due to abnormal arthrokinematics Clinical Relevance: Scapulothoracic Joint Scapulothoracic Muscles • Trapezius • Serratus anterior • Rhomboids • Levator scapulae • Pectoralis minor • Subclavius Scapulohumeral Rhythm • Total elevation: • 1200 at G-H joint • 600 at S-T joint Force Couple at Scapulothoracic Joint • Serratus anterior produces anterio-lateral movement of inferior angle • Upper trapezius pulls scapula medially Acromioclavicular Joint Sternoclavicular Joint • Joint capsule • Anterior & posterior S- C ligaments • Intra-articular disc • Interclavicular ligament • Costoclavicular ligament Sternoclavicular Joint • Protraction/retraction • Elevation/depression • Axial rotation (spin) Motions: Biomechanics of Scapular Rotation • Scapulothoracic motion occurs as part of closed kinetic chain involving: • A-C joint • S-C joint