Kuratani S
Department of Anatomy, University of the Ryukyus, Okinawa, Japan.
Anat Anz. 1989;169(5):335-49.
By studying the development of the orbital region in the Loggarhead turtle (Caretta caretta) and some placental mammals, it has become clear that the orbital region of the neurocranium should not be regarded as merely a "bowl" to contain the brain, but rather that its ventral part is originally flexured along with the cephalic flexure of the neural tube. At this flexure, the neurocranium is to be divided into 2 parts, the anterior and posterior. The anterior part of the neurocranial sheet is medially perforated by the infundibulum and gives rise to pila metoptica laterally. The post orbital cartilage represents the posterior part. From the above "Bauplan" of the neurocranium, the following conclusions can be drawn: (1) the simple homology of the reptilian and placental mammalian pila metoptica is questionable; (2) the pila antotica is produced by the absorption of the mid-dorsal part of the postorbital cartilage, while the dorsum sellae in mammals is produce by the chondrification of the middle part of the same anlage; (3) homology of the ala hypochiasmatica in mammals with the supratrabecular cartilage in reptiles is more feasible than with the cartilago hypochiasmatica; and (4) the crista sellaris in reptiles is not a part of the primary cranial wall but probably of secondary production.
通过研究蠵龟（Caretta caretta）和一些胎盘哺乳动物眼眶区域的发育情况，已明确神经颅的眼眶区域不应仅仅被视为一个容纳大脑的“碗”，而是其腹侧部分最初会随着神经管的头曲而弯曲。在这个弯曲处，神经颅被分为前后两部分。神经颅板的前部在中间被漏斗穿通，并在外侧形成额顶柱。眶后软骨代表后部。从神经颅的上述“蓝图”可以得出以下结论：（1）爬行动物和胎盘哺乳动物额顶柱的简单同源性值得怀疑；（2）前耳柱是由眶后软骨背中部的吸收产生的，而哺乳动物的鞍背是由同一原基中部的软骨化产生的；（3）哺乳动物的视交叉下翼与爬行动物的小梁上软骨的同源性比与视交叉下软骨的同源性更可行；（4）爬行动物的鞍嵴不是原发性颅壁的一部分，可能是继发性产物。
