The spinal cord is a member of the central nervous system and connects the brain with the rest of the body. It is a thick longitudinal cord of nervous tissues that extends along the back dorsal in the vertebrates, to the bodies of the vertebrae and is enclosed in the vertebral canal formed by their neural arches, it is in continuous anteriorly with the medulla oblongata and gives off interval pairs of spinal nerves to various parts of the limbs and the trunk. It is not only a pathway for nervous impulses to and from the brain, but acts as a center for carrying out and coordinating many reflex actions independent of the brain, and mainly consists of large white matter which are arranged in columns and tracts of longitude fibers along a large central core of grey matter, which is H-shaped in cross section, and pierced centrally by a small longitudinal canal, continuous with the ventricles of the brain, also called medulla spinalis. Though the spinal nerves bring information to other organs and other parts of the body, the brain sends signals to the rest of the body.
What is the spinal cord?
The spinal cord can be seen as a column of nerve fibers flowing within the spine, which connects the brain with the rest of the organism. About 1 to 1.5 cm wide and from 40 to 50 cm long, it starts at the level of the so-called foramen magnum (or occipital hole, an opening located at the base of the skull) and ends at the first or second lumbar vertebra level.
It is formed by a white substance (composed by the extensions of neurons) and from an internal grey substance (formed from the bodies of neurons) and is divided into four regions (cervical, thoracic, lumbar and sacral) each of which is formed by several segments, from which they branch off a total of 31 pairs of spinal nerves, each containing motor nerve fibers and sensory nerve fibers.
From the second lumbar vertebra the spinal cord is divided into different groups of fibers, which form the nerves directed towards the lower half of the body. This bundle of nerves travels for a distance within the spine, and takes the name of the cauda equine, and then leaves through a neural foramen.
The spinal cord is surrounded by a membrane, the dura mater, which forms a sort of protective bag in which the cerebrospinal fluid flows.
What function does the spinal cord serve?
The spinal cord belongs to the central nervous system and is the structure that connects the brain with the rest of the body, the nerves that arise from the spinal cord and are spilled over small openings located between the vertebrae (the foramina), connect with specific parts of the body. Precisely due to this, damage to the spinal cord can lead to paralysis of some parts of the body, while not in others.
Nerves in the neck area and head, towards the upper chest and arms. Those of the chest area innervate the chest and abdomen. Those in the lower back are directed instead to the intestine, the bladder and legs. Taken together all these nerve fibers coordinate and control the various body parts, organs and muscles in the body.
Moreover, the nerves also carry electrical signals from the periphery of the body fin in the brain. This allows us to feel different sensations, from heat to pain. Even nerve damage may trigger sensations, such as pain, tingling or even numbness, dependent on the area of the flow.
