Chapter 5:Part 1 The Upper Extremity: The Shoulder Region KINESIOLOGY Scientific Basis of Human Motion, 12th edition Hamilton, Weimar & Luttgens Presentation Created by TK Koesterer, Ph.D., ATC Humboldt State University Revised by Hamilton & Weimar McGraw-Hill/Irwin Copyright © 2012 by The McGraw-Hill Companies, Inc. All rights reserved.

Objectives 1. Name, locate, & describe the structure & ligamentous reinforcements of the joints. 2. Name & demonstrate movements possible. 3. Name & locate muscles & muscle groups, and name their primary actions. 4. Analyze the fundamental movements with respect to joint & muscle actions. 5. Describe common injuries.

Acromioclavicular (AC) Joint Articulation of acromion & distal end of clavicle. Acromioclavicular ligament strengthens joint superiorly. Aponeurosis of trapezius & deltoid strengthen joint posteriorly. Coracoclavicular ligament further stabilizes joint. Fig 5.1

Sternoclavicular (SC) Joint Fig 5.2 Proximal clavicle articulates with sternum and cartilage of 1st rib. Capsule thickened by anterior & posterior sternoclavicular ligaments. The only bony connection between the humerus and axial skeleton. Permits limited motion of the clavicle. Partially responsible for movements of the scapula. Clavicular movements at the SC joint: elevation & depression, protraction & retraction, forward & backward rotation.

Movements of the Shoulder Girdle Fig 5.3 a & b Abduction (Protraction) Adduction (Retraction) Elevation Depression

Movements of the Shoulder Girdle Fig 5.3 c & d Upward rotation Downward rotation Anterior tilt Posterior tilt

MUSCLES OF THE SHOULDER GIRDLE Location: Anterior Pectoralis minor, Serratus anterior, Subclavius Posterior Levator scapulae, Rhomboids, Trapezius

Pectoralis Minor Function: Movements of scapula: downward rotation, anterior tilt, depression. Lifting effect on ribs in forced inspiration and posture. Fig 5.4

Serratus Anterior Function: Abduct (protract) scapula. Fig 5.4 Function: Abduct (protract) scapula. With trapezius, upward rotation of scapula. Active in reaching and pushing.

Subclavius Function: Protect and stabilize sternoclavicular joint. Fig 5.4 Function: Protect and stabilize sternoclavicular joint. Depress scapula.

Levator Scapulae Function: Elevation and downward rotation of scapula. Fig 5.5

Rhomboids, Major and Minor Function: Downward rotation, adduction (retraction), & elevation of scapula. Works with trapezius for maintenance of good posture. Fig 5.5

Trapezius Function: I. Elevation Fig 5.6 Function: I. Elevation II. Elevation, upward rotation, adduction III. Adduction IV. Upward rotation, depression, adduction

GLENOHUMERAL (Shoulder) JOINT Structure Fig 5.7 Articulation of spherical head of humerus with small, shallow glenoid fossa of scapula. Fig 5.8 Glenoid labrum deepens the fossa and cushions impact of humeral head in forceful movements.

Ligamentous Reinforcements Fig 5.9 Coracohumeral Glenohumeral Coracoacromial

Muscular Reinforcements Superior: supraspinatus & long head of biceps. Inferior: long head of triceps. Anterior: subscapularis, pectoralis major, & teres major. Posterior: infraspinatus & teres minor.

Movements of the Shoulder Joint Internal rotation External rotation Flexion / Extension Hyperextension Circumduction Abduction / Adduction Horizontal Diagonal Internal / External Rotation

MUSCLE OF THE SHOULDER JOINT Location: Anterior: Pectoralis major, coracobrachialis, subscapularis, biceps brachii. Posterior: Infraspinatus, teres minor. Superior: Deltoid, supraspinatus. Inferior: Latissimus dorsi, teres major, long head of triceps brachii.

Pectoralis Major Fig 5.11 Function: Clavicular portion – flexion, horizontal adduction, and internal rotation of humerus. Sternal portion – downward & forward movements of arm, & internal rotation with adduction.

Coracobrachialis Function: Horizontal adduction Fig 5.12 Function: Horizontal adduction Acts like a guy wire to stabilize the shoulder joint.

Biceps Brachii Function: Flexion at the elbow & supination of forearm. Fig 5.12 Function: Flexion at the elbow & supination of forearm. Horizontal adduction at shoulder. Short head sometimes active in adduction & internal rotation.

Deltoid Fig 5.14 Function: Anterior – all forward movements & internal rotation of humerus. Middle – abduction Powerful abductor of humerus. Posterior – extension, hyperextension, horizontal extension, adduction.

Subscapularis Function: Internal rotation of humerus as part of the rotator cuff. Contributes to stability of shoulder joint. Fig 5.13a

Supraspinatus Function: Acts with deltoid in abduction of the arm. Active in flexion & horizontal extension. Contributes to stability of shoulder joint. Part of the rotator cuff. Fig 5.13b

Infraspinatus and Teres Minor Function: External rotation as part of the rotator cuff. With subscapularis depresses head of humerus. Contributes to stability of shoulder joint. Fig 5.13b

Latissimus Dorsi Function: Fig 5.14 Function: Extension & adduction of arm, internal rotation.

Teres Major Function: Internal rotation, extension, & adduction of the arm. Fig 5.15

Triceps Brachii Function: Long head assists in adduction, extension, and hyperextension of the humerus. Fig 5.15

and the shoulder (glenohumeral) joint. JOINT AND MUSCULAR ANALYSIS OF THE FUNDAMENTAL MOVEMENTS OF THE ARM ON THE TRUNK Movements of the arm on the trunk involve the cooperative action of the shoulder girdle Acromioclavicular joints Sternoclavicular joints and the shoulder (glenohumeral) joint.

Movements in the Frontal Plane Fig 5.16 Shoulder Joint: Abduction Deltoid & supraspinaus Shoulder Girdle: Upward rotation of scapula Serratus anterior; trapezius II & IV Fig 5.17 Shoulder Joint: Adduction Latissimus dorsi, teres major, pectoralis major (sternal), & post. deltoid. Shoulder Girdle: reduction of upward rotation Rhomboids & pectoralis minor.

Movements in the Sagittal Plane Shoulder Joint: Flexion Anterior deltoid & pectoralis major (clavicular). Shoulder Girdle: Upward rotation of scapula Serratus anterior & trapezius II & IV. Fig 5.18

Movements in the Sagittal Plane Fig 5.19 Fig 5.20 Shoulder Joint: Extension Pectoralis major (sternal), teres major, latissimus dorsi, post. deltoid. Shoulder Girdle: Reduction of upward rotation of scapula Relaxation of agonists Against resistance - trapezius IV, rhomboids, pect. minor. Shoulder Joint: Hyperextension Teres major, latissimus dorsi, post. Deltoid. Shoulder Girdle: Anterior tilt of scapula Pectoralis minor.

Movements in the Horizontal Plane Shoulder Joint: External Rotation Infraspinatus & teres minor Shoulder Girdle: Adduction of scapula Rhomboids & trapezius III. Fig 5.22a

Movements in the Horizontal Plane Fig 5.22b Shoulder Joint: Internal Rotation Subscapularis, teres major, latissimus dorsi, ant. deltoid, pectoralis major. Shoulder Girdle: Abduction of scapula Serratus anterior & pectoralis minor. Shoulder Joint: Horizontal Adduction Pectoralis major, ant. deltoid, & coracobrachialis. Shoulder Girdle: Abduction of scapula Serratus anterior & pectoralis minor Shoulder Joint: Horizontal Abduction Post. deltoid, post middle deltoid, infraspinatus, teres minor, long head of biceps. Shoulder Girdle: Adduction of scapula Rhomboids & trapezius III.

Diagonal Movements Diagonal forward-downward and slightly inward movement of the arm. Fig 5.23 Fig 5.10

COMMON INJURIES OF THE SHOULDER REGION: Acromioclavicular Sprain AC joint forced beyond normal ROM. Downward blow to outer end of shoulder. Fall on outstretched hand. Damage consists of tearing or severe stretching of AC ligaments.

COMMON INJURIES OF THE SHOULDER REGION: Fracture of The Clavicle Clavicle fractures have causes similar to AC sprain: Downward blow to outer end of shoulder. Fall on outstretched hand. May indicate injury by supporting injured arm. Head may be tilted toward injured side with face turned to opposite side.

COMMON INJURIES OF THE SHOULDER REGION: Dislocation of the Shoulder May be forward, downward, or posterior. Most likely when arm is forcefully abducted and laterally rotated. May occur by a blow to top of shoulder . Head of humerus is forced out of the glenoid fossa. Arm held out from side in a position of slight abduction and lateral rotation. Loss of normal rounded contour of deltoid muscle.

COMMON INJURIES OF THE SHOULDER REGION: Rotator Cuff Tears Supraspinatus (supraspinatus tendon) most often injured. Nature of injury depends on arm kinematics. Caused by overuse, falls, or violent, fast arm motion.

COMMON INJURIES OF THE SHOULDER REGION: Shoulder Impingement Soft tissue superior to humeral head pressed against acromion process. Due to overuse, inflammation, trapped bursa, degeneration with aging. Will cause pain and inflammation in shoulder.