5. Shoulder.pdf

TOPIC 5: KINESIOLOGY SHOULDER JOINT Introduction Most mobile and unstable Wide range of motion Joints in the shoulder complex First group Scapulohumeral joint (glenohumeral) Subdeltoid joint Second group Scapulothoracic joint Acromioclavicular joint Sternocostoclavicular joint First group: Glenohume...

TOPIC 5: KINESIOLOGY SHOULDER JOINT Introduction Most mobile and unstable Wide range of motion Joints in the shoulder complex First group Scapulohumeral joint (glenohumeral) Subdeltoid joint Second group Scapulothoracic joint Acromioclavicular joint Sternocostoclavicular joint First group: Glenohumeral Joint Ball and socket joint Poor stability Static or primary stabilizers -joint capsule -ligamentous complex -glenoid labrum Secondary or dynamic stabilisers -Rotator cuff Subdeltoid Joint Anatomical false joint True physiological joint Important in movement ABD shoulder subacromial bursa avoids friction Second Group: Scapulothoracic Joint Anatomical false joint True physiological joint 2 slip planes are: -omoseratic space -thoracoserratic space Great shoulder width thanks to this joint. -Protraction and retraction -Elevation and depression -Upward and downward rotation Second Group: Acromioclavicular Joint Plane joint Sliding movements, limited by conoid and trapezoid ligaments Second group: sternocostoclavicular Joint Saddle Joint Articular disc divided the cavity Slide and Roll Glenohumeral Kinematics Flexion-Extension Fixed point: glenoid twist No rolling or slide: posterior spinning Anterior translation due to posterior capsular tension. Glenohumeral Kinematics. ABD/ ADD Cranial roll of the head while gliding downwards Add —> Opposite direction Importance of the Supraspinatus action Without ABD slide, the roll compress the humerus against the coracoacromial arch: subacromial impingement. ABD Frontal Plane vs Scapular plane Sagittal not natural or functional -Front plane abd. Difficulty in reaching full ROM due to compression structures. -Scapular plane abd No structural compression More efficient Supraspinatus action Glenohumeral Kinematics. Internal and external Rotation ER: The head rolls posterior and glides anterior IR in the opposite way Simultaneous glide and roll allows head to roll over a smaller surface. AC and SCC Kinematics Only passive movements All scapular movement = clavicular movement Allow for wider ROM added to glenohumeral motion For example: shoulder abduction (total of 180 degrees): -60 degrees lateral of the scapula: 20 degrees Acromioclavicular + 40 degrees Sternoclavicular AC Joint Stabilizers Static -Joint capsule: reinforced by capsular ligaments -Ligaments: Conoid and Trapezoid ligaments. In addition to the Acromioclavicular that reinforces the joint capsule. -Articular disc Dynamic -Deltoid and upper trapezius muscles. AC Osteokinematics Upward and downward rotation Rotations adjustments in the horizontal plane Rotations adjustments in the sagittal plane SCC Joint Stabilizers Static -Fibrous capsule -Ligaments: anterior and posterior sternoclavicular, the costoclavicular on each side. -Articular disc Dynamic -There are not many muscles around -Subclavius muscle SCC Osteokinematics SCC Arthrokinematics Scapulothoracic Joint Larger shoulder amplitude thanks ST. AC and SCC movement all for ST. Elevation and Depression Elevation -SCC and AC -Scapula follows path of clavicle Opposite for depression Protraction and Retraction Protraction -Horizontal plane rotations of SCC and AC -Scapula follows clavicle path Opposite for retraction Upward rotation -Arm raise -Sum of SCC elevation and AC upward rotation Downward rotation -Arms come back -Sum of SCC depression and downward rotation AC KINETICS Muscular Actions -Proximal stabilizers -Distal mobilizers Global flexion First Stage. 0-30/60. GH Motor muscles: -anterior deltoids -Coracobrachialis -Clavicular Pectoralis major Movement limits -Coracohumeral ligament strain Second Stage. 30/60-120.STj Upward rotation of the scapula. ACj and SCCj participation Motor muscles (+previous): -serratus major -upper trapezius Movement limits: -Latissimus dorsi -Pectoralis major Third Stage. 120-180 Shoulder joint lock Spinal intervention begins In ipsilateral flexion, it produces contralateral flex. -Contraction spinal muscles opposite side. In bilateral flexion, it produces lumbar lordosis. -Bilateral lumbar spinal contraction. Extension 45-55 Involved: glenohumeral and Scapulothoracic. -Glenohumeral motor muscles. Post.deltoid, teres major and minor -Scapulothoracic motor muscles. -Rhomboids -Middle trapezius -Latissimus dorsi Global Abduction First Stage. 0-90 degrees - Motor muscles: -Deltoids, especially the middle fasciculus and Supraspinatus. - Plane of scapula Second Stage. 90-150 - Upward rotation of scapula orienting glenoids - Motor muscles: Serratus and Upper trapezius Movement limits -Maximum reached in the scapula and resistance of the adductor muscles. Third Stage. 150-180 Contralteral tilt of the spine due to contraction of the spinal muscles of the opposite side. The spinal muscles contract bilaterally, producing a lumbar hyperlordosis. Global adduction 30-45 When arm is in ABD —> the ADD is made by eccentric contraction of ABD muscles. Motor muscles -GHj flex. Pectoralis Major and Anterior deltoid -GHj extension. Teres major and minor, Latissimus dorsi -STj flex. Serratus anterior -STj extension. Rhomboids External rotation 60-70 Motor muscles: -Infrapsinatus and teres minor. The movement of scapular adduction is added by the action of the rhomboids and the middle portion of the Trapezius. Internal Rotation 75-85 Motor muscles: -Teres major -Latissimus dorsi -Subscapularis -Pectoralis Major The protraciton movement of the scapula is added by Serratus Major and Pectoralis Minor action. Muscles of the Scapulothoracic Joint Elevators Upper Trapezius Levator scapulae Rhomboids Scapulothoracic Joint depressors Lower trapezius Latissimus dorsi Pectoralis Minor Subclavius Scapulothoracic Joint Protractors Serratus Major Rotation axis SCC Scapulothoracic Joint Retractors Middle trapezius Rhomboids and lower trapezius Muscles that elevate the arm GH Muscles ABD -Anterior and middle deltoids -Supraspinatus Flexion -Anterior deltoids -Coracobrachialis ST Muscles Upward rotation of the scapula -Serratus anterior -Upper trapezius Rotator Cuff muscles FUNCTIONS: 1. Dynamic joint stability regulators 2. Arthrokinematics controllers Muscles that move in ADD and EXTEND the shoulder Major isometric moment of the shoulder -Agonists: Latissimus and Pectoralis major -Synergistic: Infraspiantus, teres minor and major. Rhomboids Stabilizers scapula in ADD and GH extension. Retraction and downward rotation All rotator cuff is active during this movement Muscles that internally and externally rotate the shoulder Internal rotators Subscapularis, anterior deltoid, Pectoralis major, Latissimus dorsi, and teres major. Head roll and slides over glenoid. External rotators Infraspionatus, teres minor, and the posterior portion of the posterior deltoid. Supraspinatus synergistic.