[The analysis of plain film presentation and bone age of achondroplasia].

Achondroplasia is the most common type of inheritant dwarfism. The diagnosis is mainly depended on clinical and plain film presentation. This study mainly focus on the characteristic presentation of plain film in achomdroplasia. We try to find the most consistent presentation and explain it through the development and growth of bone. The presentation in our 16 cases is as follows: Metaphyseal flaring 100% (16/16), Concave backs of vertebral body 100% (4/4), Short & wide tubular bone of hand & foot 85% (12/24). Square iliac bone 78% (11/14), Flare anterior end of ribs 76% (10/13), Decrease interpeduncular distance of lower L-spines 64% (9/14), Proimal < distal tubular bone 33% (5/15). Disproportionately long fibular bone 8% (1/13). We also analyze the heritant characteristics and conclude that most of achondroplasia are caused by mutation. The heritant trait is only 6%. According to bone age study, we found high percentage (31%) of delayed bone maturation.