Abstract: Objective：To measure vertical axis length of humerus head in patients with proximal humeral fractures and to evaluate the use of structure screws in proximal humerus internal locking osteosynthesis system (PHILOS). Methods:From January 2007 to February 2014,117 patients with proximal humerus fracture were treated by PHILOS plate. Preoperatively, all the patients tookanteroposterior X-ray of shoulder, and the vertical axis length of humerus head were measured, and the use of structure screws in PHILOS plate was observed.Results: There were 40 male and 77 female patients; The vertical axis length of humerus head in male patients was (47.64±3.44) mm, and the rate of structure screw use was 52.5%; The vertical axis length of humerus head in female patients was (42.46±3.21) mm, and the rate of structure screw use was 32.5%. The vertical axis length of humerus head and the rate of structure screw use had significant difference in the male and female groups （P<0.05）.Conclusion: The rate of structure screw use was low in the treatment of proximal humerus fracture by PHILOS plate, especially for women. We should improve the design of plate according to the anatomical characteristics of Chinese.

Key words: Bone plates, Humeral fracture, Structure screw