Spinal cord

Spinal cord – the department of the central nervous system of a backbone representing a cord 45 cm long and 1 cm wide.

Structure of a spinal cord

The spinal cord in the vertebral channel is located. Behind and in front there are two furrows thanks to which the brain is divided into the right and left half. It is covered with three covers: vascular, web and firm. The space between vascular and web covers is filled with cerebrospinal fluid.

In the center of a spinal cord it is possible to see gray matter, on a cut in a form reminding a butterfly. Gray matter consists of motor and internuncial neurons. The periblast of a brain represents white matter of the axons collected in the descending and ascending conduction paths.

In gray matter distinguish two types of horns: lobbies in which there are motor neurons, and back, the location of internuncial neurons.

In a structure of a spinal cord contain 31 segments. From everyone ventral and back roots which, merging, form a spinal nerve last. At an exit from a brain nerves at once break up to roots – back and front. Back roots are formed by means of axons of afferent neurons and they are sent to back horns of gray matter. In this place they form synapses with efferent neurons whose axons form ventral roots of spinal nerves.

In back roots there are spinal nodes in which sensory nervous cells are located.

On the center of a spinal cord there passes the spinal channel. To head muscles, lungs, heart, bodies of a chest cavity and upper extremities nerves depart from segments of an upper chest and cervical part of a brain. Segments of lumbar and chest parts manage abdominal organs and muscles of a trunk. Sacral and nizhnepoyasnichny segments of a brain manage muscles of the lower part of an abdominal cavity and muscles of the lower extremities.

Functions of a spinal cord

Two main functions of a spinal cord are known:

• Conduction;
• Reflex.

Conduction function consists that nervous impulses on the ascending ways of a brain move to a brain, and on the descending ways from a brain to working bodies teams arrive.

Reflex function of a spinal cord is that it allows to carry out the elementary reflexes (knee a reflex, otdergivany hands, bending and extension of upper and lower extremities, etc.).

Under control of a spinal cord only simple motive reflexes are carried out. All other movements, such as walking, run, etc., demand obligatory participation of a brain.

Pathologies of a spinal cord

If to proceed from origins of pathologies of a spinal cord, it is possible to allocate three groups of his diseases:

• Malformations – puerperal or inborn deviations in a brain structure;
• The diseases caused by tumors, neuroinfections, disturbance of spinal blood circulation, hereditary diseases of a nervous system;
• Injuries of a spinal cord to which injuries and fractures, squeezings, concussions, dislocations and hemorrhages belong. They can appear as it is autonomous, and in combination with other factors.

Any diseases of a spinal cord have very serious effects. It is possible to carry injuries of a spinal cord which statistically can be divided into three groups to special type of diseases:

• Road accidents – are the most common cause of injuries of a spinal cord. Driving of motorcycles as there is no back back of sitting protecting a backbone is especially injury-causing.
• Falling from height – can be both accidental, and intentional. Anyway, the risk of injury of a spinal cord is rather high. Often athletes, fans of extreme sports and jumps from height receive injuries in such a way.
• Home and extraordinary accidents. Often they result from descent and falling in the unsuccessful place, falling from a ladder or at ice. Also it is possible to carry knife and bullet wounds and many other cases to this group.

At injuries of a spinal cord first of all conduction function is broken that leads to very deplorable effects. So, for example, injury of a brain to cervical department leads to the fact that functions of a brain remain, but lose bonds with most bodies and muscles of a body that leads to body paralysis. The same frustration arise at damage of peripheral nerves. If sensory nerves are damaged, then sensitivity is broken in certain body parts, and damage of motor nerves breaks the movement of certain muscles.

The majority of nerves have the mixed character, and their damage causes at the same time both impossibility of the movement, and an anesthesia.

Puncture of a spinal cord

The spinal puncture consists in introduction to a subarachnoid space of a special needle. The puncture of a spinal cord in special laboratories where define passability of this body is carried out and measure liquor pressure. The puncture is carried out as in the medical, and diagnostic purposes. It allows to diagnose timely existence of hemorrhage and its intensity, to find inflammatory processes in a meninx, to define the nature of a stroke, to define the changes in character of cerebrospinal liquid signaling about diseases of the central nervous system.

Often the puncture is done for administration of X-ray contrast and medicinal liquids.

In the medical purposes the puncture is carried out for the purpose of extraction of blood or purulent liquid, and also for introduction of antibiotics and antiseptic agents.

Indications to a puncture of a spinal cord:

• Meningoentsefalita;
• Unexpected hemorrhages in a subarachnoid space owing to a rupture of aneurism;
• Cysticercosis;
• Myelites;
• Meningitis;
• Neurosyphilis;
• Craniocereberal injury;
• Liquorrhea;
• Echinococcosis.

Sometimes when carrying out operations on a brain use a puncture of a spinal cord for decrease in parameters of intracranial pressure, and also for simplification of access to malignant new growths.