The structures forming the shoulder joint are very complex and the biomechanical effects of them on the joint are not clearly lunderstood. Frequently the long head of the biceps brachii muscle is dislocated naturally and it has been said that the supratubercular ridge, the depth, and angle of medial wall of the intertubercular groove are important. And the angles between the long axis of the humerus and the axis of head and neck are important clinically. So the authors studied them in the 105 specimens of the Korean adults humerus. The results are as follows: 1. The complete type of the supratubercular ridge was present in 22.9% and the partial type was in 53.3% 2. If the ridge was present, the spur of the lesser tubercle was present in 67.5% and if not present, the spur was in 8%. 3. The angle of medial wall of the intertubercular groove was variable, and the angle less than 45 was 13.41°. 4. The angles between the long axis of the humerus and the axis of head and neck were much greater in male than female (P<0.05). 5. The average diameter of the head of the humerus was 4.42±0.4cm in male and 4.4±0.4cm in female (P < 0.05).