Objective　To provide anatomical basis for broad nasal bone reduction.  Methods　Clinical surgical dissection of nasal dorsum was studied bilaterally on 10 embalmed cadaveric head specimens.  Results  Nasal dorsum involved in nasal bone, nasal process of maxilla, and nasal process of frontal bone. The suture line length of nasal bone was about (25.2±2.91)mm, and suture line length of nasomaxillary (29.2±2.51)mm. The thickness of nasal process of maxilla at the level of piriform aperture was about (1.86±0.22)mm, at the level of the infraorbital border (2.18±0.22)mm, and at the level of medial canthal ligaments (2.78±0.10)mm. The distance between nasomaxillary groove and nasolacrimal duct was (3.52±1.22)mm for superior  part, (5.10±1.48)mm for middle part and (5.62±1.26)mm for inferior part respectively. The distance from the midpoint of insertion of the anterior branch of the medial canthal ligament to the nasomaxilloric suture was (2.87±0.08)mm.  Conclusions    For osteotomies of broad nasal bone reduction, the lateral incision have to be made from the superior part of inferior nasal concha, along with nasomaxillary groove under the periosteum and leaving the nasal lateral vein, reach to nasal root for meeting with medial incision, which is about the 3.5mm near the medial inferior aspect of orbital margin.