144 Anatomy & Physiology Essentials Copyright Goodheart-Willcox Co., Inc. the posterior aspect of the trunk, the region between each scapula and the underlying tissues is sometimes referred to as the scapulothoracic joint. The glenoid fossa (socket) of the scapula is a relatively shallow indentation that articulates, or joins, with the head of the humerus, the bone in the upper arm, to form the glenohumeral joint, or shoulder joint. Because the glenoid fossa is less curved than the humeral head, the humerus is able to glide against the The acromioclavicular joint primarily allows you to raise your arm so that you can perform movements above your head. The sternoclavicular joint enables you to move your clavicle and scapula for motions such as shrugging your shoulders, raising your arms, and swimming. The clavicle serves as a brace for positioning the shoulder laterally away from the trunk. Although there are no bony articulations between the scapulae and Clavicle Corocoid process Scapula Xiphoid process Body of sternum Anterior view Posterior view Humerus Head of humerus Spine of scapula Head of humerus Clavicle Acromion Acromioclavicular joint Spinous process of T1 Supraspinous fossa Sternoclavicular joint Manubrium 1st rib 7th rib 8th rib Costal cartilage 12th thoracic vertebrae Acromion © Body Scientific International Figure 5.20 Anterior and posterior views of the shoulder girdle, ribs, and humerus. Acromion Acromion Suprascapular notch Glenoid cavity Lateral border Subscapular fossa Lateral angle Inferior angle Spine Supraspinous fossa Medial border Superior border Infraspinous fossa Coracoid process Superior angle Anterior view Posterior view © Body Scientific International Figure 5.21 Anterior and posterior views of the scapula.