Comparative study of cephalometric measurements using 3 imaging modalities

Background

The authors conducted a study to compare 2-dimensional (2D) lateral cephalometric radiography (LCR), 2D cone-beam computer tomographic (CBCT)–generated cephalogram and 3-dimensional (3D) CBCT for assessing cephalometric measurements.

LefortⅠ颌骨整复术外部参考点确定的解剖学观测

目的 测量鼻根部到颅前窝、额窦的最短距离。为安全放置克氏针,确定外部参考点建立解部学指导。方法 选择20例正中矢状切开的成人尸头标本,使用游标卡尺,测量(1)鼻根点到前颅窝的最短距离;(2)额窦最低点到通过鼻根点水平线的最短距离。结果 从鼻根点到前颅窝的平均距离为15.6mm,从鼻根点到额窦的平均距离为4.5mm。结论 克氏针从前上向后下进入相对前颅窝和额窦为安全路径。     

正常人面中部解剖标志点与中线关系的测量研究

本研究对230名牙颌关系正常的青年人面中部解剖标志点至面中线的距离进行了照相测量分析。结果表明：鼻根点与中线的偏差较小,上唇系带与中线偏差较大,颏点与面中线的偏差最大,天然中切牙近中接触点并不都正位于中线上,约65％有偏差,幅度为－2．95mm~2.75mm。各标志点到中线的距离男女性别之间无显著性差异。鼻根点可辅助确定面部中线,其余各点可供参考。     

中国人骨性外鼻的解剖学

在150例中国成年颅骨标本上,对组成骨性外鼻的各个部分作了观测:1.鼻根部:由额骨鼻部及鼻骨上端组成,为额鼻管的前壁,厚度平均为8.08±0.11 mm。2.鼻骨:左、右多不对称,144例(96.00％)两侧鼻骨均为长方形;4例(2.67％)两侧均为三角形;2例(1.33％)左侧为三角形,右侧为长方形。测量了鼻骨的长、宽及厚度。3.上颌骨额突:分上、中、下三段观测。(1)上段位于筛前窦的前方,为筛窦手术鼻腔外入路的通道,其宽度平均为8.45±0.06mm;厚度平均为5.72±0.09mm。(2)中段为泪囊鼻腔造孔术需要凿通的部位。此段鼻部宽平均为6.77±0.05mm;泪囊窝部宽平均为4.97±0.04mm;厚度平均为4.68±0.08mm。(3)下段的前外侧面有鼻面沟,沟底为骨性外鼻与面部的分界,亦为在骨性外鼻上作外侧骨切除的重要标志。从沟底到梨状孔缘鼻颌缝下端间的宽度,平均为8.16±0.04mm;厚度平均为1.70±0.02mm。4.梨状孔缘:上部为鼻骨下缘,与上外侧鼻软骨的上缘相接;侧部为上颌骨鼻切迹的游离缘,其与鼻腔侧壁的分界为下鼻甲骨的前端。此缘到下鼻甲骨前端的宽度平均为2.62±0.07mm。对梨状孔下缘及前鼻棘,依照人类学分型原则作了观察,并讨论了它们的临床意义。     

Smaller mandibular size in infants with a history of an apparent life-threatening event

OBJECTIVES: To examine small mandibular size and preference for a hand-to-chin posture as salient characteristics in infants with a history of an apparent life-threatening event (ALTE). STUDY DESIGN: This was a prospective case-control study of term infants, from birth to 6 months of age, admitted post-ALTE and matched 1:2 with healthy control infants (age within 2 weeks and weight within 0.5 kg). Infants with confirmed gastroesophageal reflux and congenital anomalies, including severe micrognathia, were excluded. RESULTS: Infants with a history of an ALTE (n = 25) were matched to 47 healthy controls. Infants with a history of an ALTE had mandibular indices (larger index indicates a smaller mandible) that were 3.8 mm greater on the left side (95% CI: 2.0-5.6, P < .001) and 4.2 mm greater on the right side (95% CI: 2.7-5.6, P < .001) adjusting for length and non-white race. Controlling for matching and length, a 1-mm increase in the average mandibular index increased the odds of an ALTE by 62% (OR = 1.62, 95% CI: 1.22-2.44, P < .001). CONCLUSIONS: Smaller mandibular size was associated with ALTE, suggesting airway obstruction as a potential cause of ALTE. The association of this characteristic with ALTE also offers the potential for prospective quantification of ALTE risk.