spinal stenosis
SCANNING THE SPINAL CORD
The spinal cord is a highly sensitive nerve thread. It extends up to 18 inches. The spinal cord is the communication highway between the brain and other parts of the body. The spinal cord along with the brain constitutes vital parts of the central nervous system (CNS). Incidentally, the CNS is the main managing unit of our body.
THE JOB OF SPINAL CORD
The spinal cord does the linkup job via bundles of neuron or peripheral nerves. These nerves are of two types, viz., UMNs (Upper Motor Neurons) and LMNs (Lower Motor Neurons). The UMNs are the spinal tract messengers. They carry the stimuli from the brain to other spinal nerves and vice versa.
On the other hand, the LMNs communicate with targeted sections of the body. The LMNs have entry and exit points at each vertebral stage. The LMN sensory portions convey sensation information from the skin and other organs as well as body parts to the brain. The LMN motor portions carry forth messages from brain to different parts of the body. Thus, the LMN brings about movement of the muscles.
WHAT CONSTITUTES THE SPINAL CORD?
The spinal cord is made up of mainly gray matters. The spinal cord also remains surrounded by certain white substances. Most of the gray materials are dendrites and cell bodies. The white portion called tracts is made up of interneuronal axons bundles. These tracts are the messengers to and from the brain.
Whereas some tracts carry stimuli or information to the brain (hence identified as ascending) the others convey such information from the brain (therefore called descending).
THE VERTEBRA
Several bone rings called vertebrae (singular is vertebra) enfold the spinal cord. These bones go to construct the back bone or the spinal column. Depending on their locations, the vertebrae are christened. The eight Cervical Vertebrae are located in the neck. From top to bottom, they are identified as C-1 to C-8. Similarly, the dozen chest vertebrae are known as the Thoracic Vertebrae. Take for instance the top rib is attached to the first thoracic vertebra (T-1).
LOCATING THE SPINAL CORD
The spinal cord starts from the brain stem (the lower portion) and ends at the vertebra called 'L1' or the first lumbar. It passes via the vertebral backbone at the central portion of body's dorsal side. From L1, the spinal cord assumes the form of Cauda Equina. Notably, only spinal nerves continue from this stage. There is no spinal cord beyond the first or the second lumbar vertebrae.
CAUDA EQUINA
This Latin term means the tail of a horse. Cauda equina resembling the hairy tail-end of a horse is actually an extension of the spinal cord. It is made up of nerve rootlets. This structure is located at the spinal column's lower end (vertebra L3).The spinal cord remains only till the Cauda equina. These hairy roots extend the communication network to the spine end. Cauda equina stay suspended within spinal fluid.
INSULATION OF SPINAL CORD & THE VERTEBRAL COLUMN
This spinal cord stays insulated within the vertebral column. The vertebral column moves via the spinal canal. The vertebral column is made up of vertebrae. The vertebrae are divided into five clusters (from bottom to top): the coccyx, sacrum, lumbar vertebrae, thoracic and the cervical. Within each vertebrate the spinal cord is shielded by a bony casing comprising the vertebral column.
Mentionably, the spinal cord passes down to the sacral vertebrae within a human fetus. But as a person grows, his spinal cord develops slower than the body. As a consequence thereof, the spinal cord touches only the first or second lumbar vertebrae during the person's adulthood.
UNDERSTANDING SPINAL CORD INJURY (SCI)
When the spinal cord suffers any damage, it is called Spinal Cord Injury (SCI). Such SCI may even lead to serious dysfunctions. It is to be noted that a person may not have his/her spinal cord severed; but even then that person may suffer from SCI. It is important to note that SCI is vastly different from back injuries like pinched nerves, spinal stenosis, and ruptured disks.
An SCI cannot happen only if the bones (the vertebrae) surrounding the spinal cord are damaged and the spinal cord is not affected at all. Mentionably, if the vertebrae are damaged the patient may not even suffer immediate paralysis if those broken vertebrae get stabilized following a surgery.
RECURRENT SCI EFFECTS
A person having recurrent SCIs may even lose mobility and the sense of feeling. The two major causes of such frequent SCIs are diseases and trauma. The diseases that lead to SCI are among others Friedreich's Ataxia, spina bifida, and polio. Trauma can be the result of sudden shocking events like gun shots, and vehicle accidents, to mention but two.
NERVE & SPINAL CORD STRUCTURES
Among the prominent spinal cord and nerve structures are the Cerebrospinal Fluid (CSF), Meninges and Dermatones. The Cerebrospinal Fluid (CSF) is a shock absorber. This clear fluid moves around the tissues. It is also the primary agent shielding the spinal cord from any injuries. The CSF is located within the spinal cord, the spinal canal and the Ventricles (brain chambers). This clear liquid gets secreted from the brain's ventricles (forming the vascular portion) known as the Choroids Plexus. The CSF consists of various glucose, proteins, and electrolytes. A normal adult generally possesses approximately 150 milliliters of CSF.
The Meninges provide the membrane protection cover to the spinal cord and the brain -- the two main agents of the Central Nervous System. Meninges are of three types viz., Pia Mater, Arachnoid Mater, and Dura Mater. The highly vascular and most delicate membrane is the pia mater. Our neural structures get blood from these membranes. The arachnoid mater is made up of veins and arteries. A fluid known as the cerebrospinal fluid fills up the Subarachnoid space. The dura mater layer is thicker than arachnoid mater. The dura mater makes up the outer layer of the nerve roots and the spinal cord. It is gray in color. It is made up of sturdy connective tissues. The Dermatome is made up of skin mater. This portion is constituted of fibers that emanate from the root of a spinal nerve.
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