摘要：Objective: To investigate the role of the lateral pterygoid muscle in the new bone formation during healing of sagittal fracture of the mandibular condyle. Methods: Oblique sagittal fracture on the right condyle of 24 adult sheep was made by osteotomy. In the control group(n = 12) the lateral pterygoid muscle was cut, and in the experimental(n= 12) was not. 4 sheep were killed at 4, 12 and 24 weeks after operation respectively. Three-dimensional reconstruction was performed by micro-CT, the tra-becula number (Tb. N) , trabecula thickness ( Tb. Th) , trabecula space (Tb. Sp) and bone volume fraction ( BV/TV ) of the fractured condyles were measured, the data were analyzed by SPSS 13. 0. Results: The shape of condyle was changed more in the experimental group than in the control. In the experimental group Tb. N, Tb. Th and BV/TV increased (P <0. 05) , Tb. Sp decreased (P <0.05). The parameters in the 2 groups were statistically different (P <0.05). In the control group the parameters were not significantly changed(P > 0. 05 ) . Conclusion: The lateral pterygoid muscle can promote the new bone formation in the reconstruction of the mandibular condyle during healing of sagittal fracture.%目的:观察翼外肌在颞下颌骨髁突矢状骨折愈合时新骨形成中的作用.方法:24只绵羊随机分为2组,每组各12只,实验组:髁突截骨术造成绵羊右侧髁突矢状骨折,保留翼外肌；对照组:髁突截骨术造成绵羊右侧髁突矢状骨折,离断翼外肌.分别于术后4、12、24周3个时间点实验组及对照组各处死4只动物,进行显微CT(Micro-CT)扫描,观察分析骨折区新生骨的骨小梁数量(trabecula number,Tb.N),骨小梁厚度(trabecula thickness,Tb.Th),骨体积分数(bone volumefraction,BV/TV)及骨小梁间隙宽度(trabecula space,Tb.SP)的变化,并用方差分析法对数据进行统计学分析.结果:实验组髁突形态改变较对照组明显,显微CT图像新生骨小梁结构显示清晰,Tb.N、Tb.Th、BV/TV增加(P＜0.05),Tb.Sp减小(P＜0.05),组间比较差异均具有统计学意义(P＜0.05),对照组各参数变化无统计学意义(P＞0.05).结论:翼外肌在颞下颌关节矢状骨折愈合过程有促进新骨形成的作用.