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Evaluation and Treatment of the Shoulder Complex: Summary
INTRODUCTION SHOULDER COMPLEX: ANATOMY OVERVIEW
LEARNING TIP! It is important to note that the scapulothoracic junction is not a joint because it does not contain a capsule or a ligamentous support.
It is important to understand the anatomy of the shoulder complex. The shoulder complex is made up four bones (the scapula, clavicle, humerus, and thorax) as well as the thoracic spine and rib cage. Connective tissues associated with the shoulder complex include the glenoid labrum, ligaments, joint capsule, and bursas. The thorax component of the shoulder complex contains 12 vertebrae, 24 ribs, and the sternum. The thorax is composed of 63 articulations and 24 nerve roots, 12 on each side. The nerves of the thorax are known as the intercostal nerves. The shoulder complex is comprised of four articulations, three joints and one junction: The glenohumeral (GH) joint, acromioclavicular (AC) joint, sternoclavicular (SC) joint, and scapulothoracic junction.
The glenohumeral joint is a synovial joint. This is a joint capsule, articular cartilage, ligaments within the joint capsule, and synovial fluid inside the joint capsule. The role of synovial fluid is to provide cushioning and nutritional support while liberating joint surfaces to increase range of motion without causing discomfort. The ligaments of the shoulder complex are composed of three primary glenohumeral ligaments within the glenoid labrum: The coracohumeral ligament, middle ligament, and inferior ligament (see pictures below, where ligaments are highlighted in green). Each ligament helps to prevent excessive movement through the various range of motion the shoulder moves through, with all three GH ligaments limiting external rotation.
Shoulder Complex Ligaments Ligament
Motion Limited
Origin and Insertion
Coracohumeral
Excessive flexion, extension, and external rotation
Coracoid process and greater tubercle of humerus
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