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Shoulder Girdle. Function and Nature. Connects upper limbs/arms to axial skeleton Affords extreme mobility Somewhat unstable. Bones. Scapula Clavicle Coracoid. Joints. Shoulder girdle is comprised of 5 joints; 3 are true anatomical joints and 2 are false, or physiological joints.
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Function and Nature • Connects upper limbs/arms to axial skeleton • Affords extreme mobility • Somewhat unstable
Bones • Scapula • Clavicle • Coracoid
Joints • Shoulder girdle is comprised of 5 joints; 3 are true anatomical joints and 2 are false, or physiological joints
Anatomical Joints • Sternoclavicular joint: • only place where shoulder girdle is attached to axial skeleton • synovial saddle joint that functions like a ball and socket joint • articulates medial end of clavicle w/manubrium or sternum • has 60 °range of motion in response to scapular elevation
Anatomical Joints • Glenohumeral/scapulahumeral joint • ball and socket synovial joint that articulates head of arm bone and glenoid cavity of scapula • facilitates abduction, adduction, medial/internal and lateral/external rotation, flexion and extension of the arms
Anatomical Joints • Acromioclavicular joint • plane type synovial joint that articulates lateral end of clavicle w/acromiom process of scapula • scapular acromiom rotates on clavicular end
Physiological/False Joints • articulations formed by muscles, tendons and ligaments • 2 in shoulder girdle • scapulocostal/scapulothoracic • suprahumeral/subacromial
Scapulocostal/Scapulothoracic • gliding joint formed by the articulation of the anterior scapula and the posterior thoracic rib cage • held together by tendons and muscles, the most important of which are the rhomboids, trapezius, and serratus anterior; pectoralis minor assists • facilitates elevation, depression, protraction and retraction of shoulder blades
Suprahumeral/Subacromial • ligamentous joint formed by by the gap between the head of the arm bone/humerus and the acromium process or the scapula • affords complex movements while arm is fully flexed as in changing light bulb or painting ceiling
space filled by suprasinatus muscle and by bursa; coracoacromial ligament articulates w/head of arm bone to form joint
information from http://en.wikipedia.org/wiki/Pectoral_girdle