Mercier J, Gordeeff A, Delaire J
Orthod Fr. 1989;60 Pt 2:575-82.
The ramus of the mandible appears with the cephalic hominisation phenomenous during phylogenesis and determines the vertical posterior height of the face. Among the three skeletal units that form it, the condylar one is responsible of this height and of the level of the posterior part of the occlusal plane. So, all congenital, constitutional or acquired diseases concerning this unit, give a change of the vertical posterior height of the face. The excess troubles ar essentially represented by the condylar hyperplasia, usually unilateral and treated by condylectomy. The vertical posterior insufficiency may be unilateral or bilateral. The former looks like a mandibular asymmetry whereas the latter looks like an anterior vertical excess with or without a Class II malocclusion. If the condyle is absent or T.M.J. destroyed like in ankylosis, the authors use the costo-chondral graft to repair it. But in condylar hypoplasia, they use a vertical osteotomy of the ramus for lengthening the ramus. The three-dimensional architectural analysis is very useful for studying the vertical posterior height of the face and his changes.
下颌支在系统发育过程中随着头部人类化现象出现，并决定面部的垂直后部高度。在构成下颌支的三个骨骼单元中，髁突单元决定了这一高度以及咬合平面后部的水平。因此，所有涉及该单元的先天性、体质性或后天性疾病，都会导致面部垂直后部高度的改变。过度问题主要表现为髁突增生，通常为单侧，通过髁突切除术治疗。垂直后部不足可能是单侧或双侧的。前者表现为下颌不对称，而后者表现为前部垂直过度，伴有或不伴有II类错牙合。如果髁突缺失或颞下颌关节如关节强硬那样遭到破坏，作者们会使用肋软骨移植来修复它。但在髁突发育不全的情况下，他们会采用下颌支垂直截骨术来延长下颌支。三维结构分析对于研究面部垂直后部高度及其变化非常有用。
