Nerves - bundles of nerve fibers enclosed in connective tissue membrane (epidavre), connecting the brain and spinal cord with the skin, muscles and other organs, and tissues. Major nerves called nerve trunks. Fiber bundles in the nerves form vnutristennaya plexus, sometimes beams are parallel to each other. Connective tissue sheath of nerve enters the nerve, surrounding the fascicles of its constituent of nerve fibers (perimetry) and single-fiber (endometrii). In it are the blood and lymphatic vessels and nerve endings. On the periphery of the nerve branches and ends in organs and tissues end ramifications are included in the nerve fibers.
A collection of nerves in the human body forms the peripheral nervous system (color table).
On the basis of origin, structure and functions there are two parts: physical, control striated muscles, bones, joints, skin, and the autonomic nervous system (see).
From the brain depart 12 pairs of cranial nerves (see), from the spinal cord - 31 pairs of spinal nerves that distinguish respectively segments of the spinal cord.
The initial part of the nerve as it comes out of the brain called the root. Each spinal nerve begins two roots - front, motor, and back, sensitive.
The location distinguish surface, or skin, nerves and deep nerves, lying under the fascia. Nerves are often connected to each other bundles of nerve fibers, forming different types plexus.
Functions are distinguished: motor nerves, which include motor nerve fibers are directed to a striated muscles, and sensitive, consisting of sensitive nerve fibers directed into all tissues, and mixed, containing both types of nerve fibers. In addition, isolated vasomotor nerves that contribute to the reduction of muscles of a wall of vessels, and secretory, causing the secretion of the glands.
Excitation in the nerve is carried out separately for each nerve fiber. Through the damaged area nerve stimulation is not carried out, leading to dysfunction of the body that this nerve innerviruetsya. When the nerve transection nerve fibers in it degenerate, breaking up into fragments, and in place of transection formed a scar, through which it is possible germination Central processes (associated with the body of the nerve cells and nerve fibers. When regeneration of nerve grows at a rate of 1-4 mm per day. Conductivity of the nerve may be temporarily impaired under the influence of some medicinal substances. This is used in medical practice, for example in anesthesia.
Nerve damage can be closed or open. The latter often occur at a firearm, knife wounds with open fractures of extremity bones. Closed injuries occur when diaphyseal and intra-articular fractures (shoulderbones of the elbow joint), the compression of the limbs, bruises. Isolated nerves are rare.
The following types of nerve damage: 1. Shake the nerves (traumatic power passes near the nerve trunk), accompanied by a short violation of motor and sensory functions of the nerves with their full recovery in future. 2. The nerve injuries, when the continuity of his remains, but the structure is undergoing changes due to compression, hemorrhage. Loss of functionality while longer than concussion; restoration of nerve begins a few weeks after the injury. 3. Anatomical break nerve, which can be partial or complete. At last there is visible to the eyes break axial cylinders and membranes of nerve. At partial breaks may experience side defect of the nerve trunk. Full anatomical break nerve leads to heavy precipitation functions and is characterized by symptoms of peripheral paralysis: muscular atrophy, atony, areflexia and reaction of degeneration of the nerve. In the area of innervation of the damaged nerve violated sensitivity, up to its complete disappearance, and motor function of muscles, developing trophic disorders. In case of incomplete break nerve, in addition to loss of sensation, there are phenomena of his irritation: pain, paresthesia, hyperesthesia. Sometimes unbearable pains are burning in nature (see Causalgia). With complete and partial interruption of nerve can develop contractures.
Closed nerve damage are subject to conservative treatment (physiotherapy, physical therapy, injections of vitamin B12 prozerina, balneotherapy , and so on). If no effect is shown revision nerve. The sooner the nerve sewn, the faster and more complete restoration of its functions, so when you open the damage should be imposed primary closure nerve. (see Nervous seam). Secondary (deferred) seam it is advisable to apply as early as possible, but after complete healing of the wound. When events compression of a nerve produces the operation of neurolite (see).
Operations on the nerve trunks - neurotomy (see), nephrectomy (see) and other generally performed under local infiltration anaesthesia (see). During the operation, use round needles (preferably atraumatic), fine silk, neurotomy with special blades, equipment for determining the conductivity of the nerve.