| Flexures | |
|---|---|
&sq=Google&lang=en&file=File:Gray651.png) Brain of human embryo of four and a half weeks, showing the three flexures | |
| Details | |
| Identifiers | |
| Latin | flexura |
| TE | (embryology)_by_E5.14.3.3.0.0.3 E5.14.3.3.0.0.3 |
| Anatomical terminology | |
Three flexures form in the part of the embryonic neural tube that develops into the brain. At four weeks gestational age in the human embryo, the neural tube has developed at the cranial end into three swellings – the primary brain vesicles. The space into which the cranial part of the neural tube is developing is limited. This limitation causes the neural tube to bend, or flex, at two ventral flexures – the rostral cephalic flexure, and the caudal cervical flexure. It also bends dorsally into the pontine flexure. These flexures have formed by the time that the primary brain vesicles have developed into five secondary brain vesicles in the fifth week.