Vertebral column and sacral curvatures) form during fetal development. The secondary curves develop after birth. The cervical curvature forms as a result of lifting the head and the lumbar curvature forms as a result of walking. The vertebral column surrounds the spinal cord which travels within the spinal canal, formed from a central hole within each vertebra. The spinal cord is part of the central nervous system that supplies nerves and receives information from the peripheral nervous system within the body. The spinal cord consists of grey and white matter and a central cavity, the central canal. Adjacent to each vertebra emerge
Jack (given name) of the word is linked to the name being used as a by-name for a man. Jack (given name) Jack is a male given name. In recent decades, Jack has become one of the most common names for boys in many English-speaking countries. While Jack is now a proper name in its own right, in English; it was traditionally used as a diminutive form of John. It can also be used as a diminutive for: Jacob, Jason, Jonathan, Johann, Johannes, Joachim and sometimes for James, from its French form Jacques. It is also used as a female given name (often