Spinal Cord:
The central nervous system consists of the brain and the spinal cord, the cerebro-spinal centre or axis. The continuation of the Medulla oblongata or the Bulb is a connecting medium between the brain and the spinal cord. The centre in the Medulla oblongata is closely connected with the involuntary functions of breathing and swallowing. The spinal cord extends from the top of the spinal canal to the second vertebra of the coccygeal region where it tapers off into a fine silken thread, called Filum terminale.
The spinal cord is a column of very soft grey and white brain-matter. The white matter is arranged on the sides of the grey matter. The white matter is of medullated nerves while the grey is of nerve-cells and fibres.
This is not tightly fitted with the spinal canal, but suspended or dropped, as it were, into the spinal canal just like the brain in the cranial cavity. This is nourished by the membranes. Spinal cord and brain float in the cerebro-spinal fluid.The fluid prevents, therefore, any injury done to them. Further the spinal cord is protected by a covering of fatty tissue. It is divided into two symmetrical halves by an anterior and posterior fissure. In the centre there is a minute canal, called canalis centralis. Brahmanadi runs along this canal from the Muladhara to Sahasrara Chakra. It is through this Nadi, Kundalini, when awakened, passes to Brahmarandhra.
The spinal cord is not divided or separated from the brain. It is continuous with the brain. All the cranial and spinal nerves are connected with this cord. Every nerve of the body is connected with this. The organs of reproduction, micturition, digestion, blood-circulation, respiration are all controlled by this spinal cord. Spinal cord opens out into the fourth ventricle of the brain in the medulla oblongata. From the fourth ventricle it runs along the third, then the fifth ventricle of the brain and finally it reaches the crown of the head, Sahasrara Chakra.
