Abstract:

Objective　To provide anatomic basis for the internal fixation of proximal humeral fracture. Methods　20 shoulder joint specimens from 10 adult cadavers were dissected. Axillary nerves were isolated from the muscle bundle interspace of deltoid, and followed by the insertion of the plate between the nerve and humerus, under the apex of greater tuberosity and behind the intertubercular sulcus. The distances from the superior border of axillary nerve to the apex of greater tuberosity and the superior border of acromial bone were measured and analyzed. The proximal humerus connected with the plate were resected for observing the relationship of the head and neck of humerus with the plate, while, the distance from the upper border of the plate to the apex of greater tuberosity, from the anterior border of the plate to the intertubercular sulcus were measured.　Results　The distances from axillary nerve to the apex of greater tuberosity and the superior border of acromial bone were separately (3.44±0.38)cm and (5.44±0.62)cm；The distance from the upper border of the plate to the apex of greater tuberosity was (5.44±0.62) cm, as well from anterior border of the plate to the intertubercular sulcus (0.74±0.19) cm. The screws paralleled with the neck of humerus and located in the middle of it when the plate placed 0.5mm below the apex of greater tuberosity, and 0.5cm behind the intertubercular sulcus.　Conclusions　(1) The site below the greater tuberosity about 29~43.2 mm is the dangerous area for damaging axillary nerve during the anterolateral acromial approach. (2) The optimal plate inserting position is below the apex of greater tuberosity about 0.5cm, and behind the intertubercular sulcus about 0.5cm. (3) The screw holes of C，D and E of PHILOS, as well that of C and D of LPHP, are dangerous zones during the fixation approach.

Key words:  Proximal humeral fracture, Applied anatomy, interal fixation, Minimal invasive surgery