There is a definite connection of skin receptors with the central nervous system , provided by nerves located in tissues and organs. Thus, the innervation of the hand is the nerves through which the receptors of the hand are connected to the central nervous system.
The nerves located in the tissues of the hand provide control over the bending arm in the fingers, elbow and wrists of the muscles. And on the palms of a person there is a huge number of receptors with which the skin nerves are connected. Four main nerves provide innervation of the hand - these are the radial, musculocutaneous, ulnar, and also median. These nerve fibers transmit information from the hand and upper arm directly to the brain, and also control the muscles. The musculocutaneous and radial nerves control all parts of the hand to the wrist. The elbow and median are only located below the elbow.
Nerves brush
The median, radial, as well as ulnar nerve fibers provide tactile, temperature and pain sensitivity of the hand, passing through all its departments and ending with receptors located on the fingertips.
Median nerve
What will happen if the innervation of the brush is disrupted?
If the median nerve is damaged, a weakening of the flexion movement of the hand or some fingers can be noted. In this case, the following symptoms may be observed:
- Pathological changes in radial muscle fibers. In this case, there is difficulty in abduction of the first finger.
- A brush with an affected median nerve resembles a monkey paw, and paresthesia is present in the palm of the hand and the first, second and third fingers.
- There may be a violation of the vasomotor and secretory functions, as a result of which the first three fingers have a bluish tint or pallor, and the nails become brittle and dull.
- Soft tissues gradually atrophy or ulcerate.
- With such a violation, it is likely that the thumb will be reduced, and its abduction or squeezing into a fist will become impossible.
- The patient cannot hold a sheet of paper between the second and first fingers. Almost all forms of capture are lost, since a violation of the median nerve implies the impossibility of opposing the first finger.
What else can disrupt the innervation of the fingers of the hand?
Ulnar nerve
The palmar muscle is supplied with the superficial palmar branch of the ulnar nerve. He is partially responsible for the movement of the fingers. The ulnar nerve is divided into two rays, which provide the sensitivity of the fifth and fourth fingers. If these nerves are damaged, then the fingers cannot make abduction and adduction movements. In general, the muscles of the hand, their blood supply and innervation are a rather fragile mechanism.
The deep part of this nerve fiber is responsible for the work of the little finger, namely its short flexor. And also for the opposing and abducting muscles of this finger. In addition, the nerve provides some of the movements of the thumb.
In violation of the functions of the ulnar nerve leads to the fact that the patient can not perform some of the actions with the hand that was hit. This is especially noticeable when comparing the movements of both hands.
The sensitivity of the medial side of the palm and little finger is sometimes lost, and because of this, the patient tries to limit the manipulations performed by the affected hand. For example, when writing, the patient presses his palm firmly against the table. A sick hand also gets tired quickly.
Innervation of the brush is very important.
Radial nerve
The fibers of this nerve provide sensitivity to the skin located on the back of the hand.
The radial nerve innervates the extensor muscles of the fingers, forearms and hands. Sensitive fibers cover the back of the hand, forearm and first, second and third fingers. If we talk about injuries, then, as a rule, they affect the nerve in the middle third of the shoulder, which is accompanied by sagging brush. At the same time, the fingers are bent and hang down stepwise. The abduction of the first finger is broken.
Inability to compress the brush
Also, with such a violation of the innervation of the hand, it becomes impossible to compress the palm into a fist or actively extend the arm in the wrist joint. To perform these actions, the patient seeks to fix the arm in the forearm. Tactile sensitivity is also weakened, while pain is not impaired. All this can be accompanied by swelling of the limb, its cyanosis and swelling of the back of the hand.
Often the innervation of the thumb of the hand is disrupted.
Damage to nerve fibers is usually accompanied by complications such as ruptures of tendons and blood vessels, bone fractures, and so on. Injuries in this case can be either open or closed - all these factors are taken into account when diagnosing damage to nerve fibers and prescribing treatment.
Tunnel syndrome
Recently, a disease such as tunnel syndrome has become extremely common. It is associated with impaired functioning of the nerves of the hands, namely, caused by compression of the median nerve. As a rule, I associate it with prolonged use of the computer muscle. Recently, the anatomical computer mouse is becoming more popular - precisely because its use allows you to avoid the occurrence of this pathology.
Symptoms of the development of the tunnel syndrome are as follows: at first the patient experiences mild, dull pain in the hand, numbness or discomfort in her joint, which usually occurs after several hours of working at the computer. If you interrupt the work and arrange a warm-up for your hands, then the pain can recede for a short period. But the constant work and the unchanging position of the hand with its partial activity leads to stagnation of blood.
How to avoid the development of tunnel syndrome?
The development of tunnel syndrome can be avoided, and for this it is not even necessary to acquire an anatomical computer mouse. It is enough to regularly perform the following three exercises:
- Squeeze your fingers tightly into a fist, and then, with the same force, unclench them. Repeat several times. And then again squeeze your hand into a fist and intensively turn them in different directions.
- The palms must be pressed firmly against one another, and the elbows should be pulled apart. The forearms should be strictly parallel to the floor. In this position, try to lower your palms as low as possible without opening them.
- Take a soft ball (you can massage) for the hands and squeeze it with all your fingers (opposite the big one) in turn. Do the same with your whole palm and two hands.
Methodology for the study of violations
The doctor carefully examines the external integument and conducts a visual comparative characteristic of the upper limbs. Necessarily takes into account the patient's complaints about decreased sensitivity and muscle atrophy. A preliminary diagnosis is established on the basis of anamnestic data and a symptomatic picture of pathological manifestations.
The most affordable diagnostic study is to determine the sensitivity of the fingers, so you can understand the nature of the lesion and impaired innervation. In the first week, all symptoms are most pronounced. In the future, the picture may be smoothed out, this is due to the overlap of the nerve zones.
We examined what the innervation of the muscles of the hand and its disorders.