Lee S K, Kim Y S, Jo Y A, Seo J W, Chi J G
Department of Pathology, Seoul National University College of Medicine, Korea.
Anat Rec. 1996 Dec;246(4):524-34. doi: 10.1002/(SICI)1097-0185(199612)246:4<524::AID-AR11>3.0.CO;2-Q.
The cranial base is not only an end result of complex segmental growth of rostral end of axial skeleton but also has a tremendous impact on the development of the brain and facial structure. However, little is known about the method for the systematic analysis of the shape of the cranial base in the developing human fetus. We used roentgenograms of the cranial base and eviscerated bones for the assessment of the development of the cranial bony complex.
The cranial base was removed from 64 normal human fetuses after 18-40 weeks of gestation. Roentgenograms were taken perpendicular to the cranial base. Major anatomical landmarks are defined as follows: the center of pituitary fossa of sphenoid bone (point S), the growth center of zygomatic bone, the anterior point of nasal septum, otic cartilage, and anterior and posterior growth centers of maxilla. The anterior cranial base angle, the middle cranial base angle, the posterior cranial base angle, the maxillary trapezoid area, the horizontal middle face area, and the occipital cranial base triangle area are defined from the landmarks, and the growth of each parameter was analyzed by gestational age.
The proportional growth of the anterior, middle, and posterior cranial fossae could be assessed by the angles around the center of the pituitary fossa (point S) and by the anterior, middle, and posterior cranial base angles. The anterior cranial base angle was relatively constant during the fetal period at 107.4-112.5 degrees, whereas the middle cranial base angle gradually increased, and the posterior cranial base angle decreased. With increasing gestational age, the horizontal middle face area increased rapidly, in contrast to those of the maxillary trapezoid area, occipital cranial base triangle area, or foramen magnum area.
The important keys in the structural development of the normal human cranial base are anterior, middle, and posterior cranial base angles. We could define the developmental pattern of human cranial base, which in turn provides a model of a standard growth pattern applicable to the study of the different malformations in the craniofacial structure.
颅底不仅是轴骨骼头端复杂节段性生长的最终结果，而且对脑和面部结构的发育有巨大影响。然而，关于系统分析发育中的人类胎儿颅底形状的方法知之甚少。我们使用颅底和去内脏骨骼的X线片来评估颅骨复合体的发育。
从妊娠18 - 40周后的64例正常人类胎儿中取出颅底。拍摄垂直于颅底的X线片。主要解剖标志定义如下：蝶骨垂体窝中心（点S）、颧骨生长中心、鼻中隔前端、耳软骨以及上颌骨的前后生长中心。从前述标志定义前颅底角、中颅底角、后颅底角、上颌梯形面积、水平中面部面积和枕颅底三角面积，并按胎龄分析各参数的生长情况。
前、中、后颅窝的比例生长可通过垂体窝中心（点S）周围的角度以及前、中、后颅底角来评估。胎儿期前颅底角相对恒定，为107.4 - 112.5度，而中颅底角逐渐增大，后颅底角减小。随着胎龄增加，水平中面部面积迅速增加，而上颌梯形面积、枕颅底三角面积或枕骨大孔面积则不然。
正常人类颅底结构发育的关键在于前、中、后颅底角。我们可以定义人类颅底的发育模式，这反过来又提供了一个适用于研究颅面结构不同畸形的标准生长模式模型。
