康复专业英语基础读本

The bones of the upper extremityconnect with the trunk through the shoulder girdle which includes the scapula, sternum,clavicle, and proximal humerus. These 4 bones are linked through one non-synovial joint (the scapulothoracic), and three other synovial joints (the sternoclavicular joints,acromioclavicular joints, and glenohumeral joints). The glenohumeral joint articulates between the glenoid cavity of the scapula and the humeral head and is the main one of these four joints. When you raise your arm, the motion of the shoulder is the result of these four joints acting together. The distal humerus connects with the forearm through the elbow joint. The forearm includes two bones: the radius and the ulna, which further connects to the carpal bones through the wrist joint. In the hand, the metacarpal bones articulate with the carpal bones proximally and with the phalangeal bones distally. There are only two phalangeal bones for the thumb, while each of the other four f ingers have three phalangeal bones: the proximal, middle, and distal phalanxes.