Cosmetologist "jack of all trades": what you need to know about brushes

Anatomical characteristics of the hand

The complex anatomical structure of the hand, its subtle and diverse functions have determined the specificity of the skin, which is significantly different in structure from the rest of the skin.

The skin on the dorsum of the hand is elastic, mobile, easily stretched and folded. This structure allows us to freely bend and straighten the hand and fingers. Subcutaneous tissue is poorly developed, consists of loose connective tissue and is characterized by the presence of a rich venous network and lymphatic vessels. The skin of the palm, on the contrary, is dense and inactive due to fusion with the palmar aponeurosis. This provides a firm, strong grip and hold on the item. The palmar surface is devoid of hair follicles and sebaceous glands, due to which atheromas, boils, and carbuncles do not occur here.

Considering that the hand has a complex structure and consists of many bones, ligaments, joints, tendons and nerves, when carrying out aesthetic procedures in this area, it is very important for specialists not only to know anatomy, but also to have an accurate understanding of the most dangerous areas during manipulation. Namely, about places of more superficial location of functionally important structures, the danger of damage to which is most likely. On the palmar surface of the hand, such zones are two elevations: the thumb ( thenar ) and the little finger ( hypothenar ). The proximal third of the longitudinal skin fold of the hand, separating the thenar from the palmar aponeurosis, is the forbidden “Kanavel area” , in which the motor branch of the median nerve passes ( Fig. 1 ). When it is contused or damaged, the important function of the muscles of the eminence of the first finger is disrupted. The median nerve on the hand is projected at the proximal edge of the skin fold that separates the tenor area from the middle palmar part. This is important to know when using botulinum toxin preparations, which, when administered deeply, can provoke paresthesia in the area of innervation (palmar surface of the 1st, 2nd, 3rd, 1/2 4th fingers) and cause a decrease in hand strength in the patient.

Rice. 1. Projection zone of the motor branch of the median nerve – “Kanavel’s area”

An equally important area is the “anatomical snuffbox” - a depression in the dorsal surface of the wrist at the radial edge of the hand, which is clearly visualized when the first finger is abducted ( Fig. 2 ). The radial artery is projected into it, and there is a danger of its damage by the injection needle with the formation of a hematoma.

Rice. 2. Projection zone of the radial artery “anatomical snuffbox”

At the apex of the styloid process of the ulna, a branch of the ulnar nerve is projected, which is located quite superficially, so deep immersion of the needle in this area should be avoided.

Also, special attention should be paid to the anatomical features of the location of the tendons and palmar synovial sheaths, which begin from the metacarpophalangeal joints and continue to the base of the nail phalanges (Fig. 3). The tendon sheath of the first finger communicates with the radial, and the fifth with the ulnar synovial bursae, which creates favorable conditions for the spread of infection in the hand area. Thus, due to anatomical features, purulent-inflammatory processes of the hand and fingers are dangerous due to the rapid transition of inflammation from the skin, subcutaneous tissue to the joints, tendon, muscle and bone apparatus.

Rice. 3. Anatomical and topographical location of tendons and palmar synovial sheaths

Analysis of statistical material from various authors allows us to conclude that it was minor injuries that did not cause concern among specialists before performing various cosmetic procedures and were the main cause of inflammatory complications after the procedure. The following complications are often encountered: thenar and hypothenar phlegmons, phlegmons of the median palmar space (supra-, subgaleal) phlegmons, crossed (U-shaped) phlegmons.

Absolute contraindications for aesthetic injections in the hand area are minor skin damage, puncture wounds (with needles, wire, wood chips, metal shavings, etc.), scratches caused by animals, as well as abrasions, inflamed calluses, skin cracks. We consider tumors, tumor-like formations and various diseases of the hand (stenosing ligamentitis, Dupuytren's contracture) to be no less important contraindications for aesthetic procedures in the hand area, which a cosmetologist can identify at the patient's first visit.

Carrying out anesthesia

Knowledge of the peculiarities of the passage of nerves in the hand area allows the cosmetologist to master the skills of performing conduction anesthesia for particularly painful manipulations, such as, for example, botulinum therapy for hyperhidrosis of the palms. Infiltration anesthesia in such cases is unacceptable, and application anesthesia, unfortunately, in most cases is ineffective.

During painful procedures in the hand area, conduction anesthesia reliably ensures a complete absence of pain with a clear consciousness of the patient.

When conduction anesthesia is performed correctly, nerve impulses are blocked along the ulnar, median and sensory branches of the radial nerve . At the time of its implementation, the patient feels slight discomfort, a short-term feeling of heaviness, fullness, and heat when the drug is administered ( Fig. 4 ).

Rice. 4. Conduction anesthesia according to Brown: 1 – zone of blockade of the median, 2 – ulnar,
3 – radial nerves

Anesthesia begins from the median nerve . The needle is inserted 1 cm proximal to the line of the wrist joint, at the ulnar edge of the flexor carpi radialis tendon. It is easy to determine when the thumb is abducted and the hand is flexed to the radial side. They use a thin short needle, which is inserted to a depth of 0.5–0.7 cm, moving it in a fan-shaped manner transversely to the course of the median nerve, trying to obtain paresthesia. Advancement of the needle is stopped and after a mandatory aspiration test (pulling the syringe piston towards itself), 5–7 ml of a 1–2% anesthetic solution (Lidocaine, Xylocaine) is injected; when removing the needle, another 2–3 ml of solution is injected (thus blocking the palmar branch of the median nerve). If paresthesia cannot be obtained, up to 10 ml of anesthetic is injected in a fan-shaped manner.

The second is to anesthetize the ulnar nerve . The needle is inserted 2 cm proximal to the line of the wrist joint, at the radial edge of the flexor carpi ulnaris tendon. Obliquely, at an angle of 60–70°, moving the end of the needle in a fan-shaped manner, they try to obtain paresthesia, after which 4–5 ml of a 1–2% anesthetic solution are injected (after performing an aspiration test). To block the dorsal branch of the ulnar nerve, 2–3 ml of anesthetic solution is injected into the tissue in the area of the palmar surface of the head of the ulna.

The last to be anesthetized is the superficial branch of the radial nerve . To do this, a needle is inserted 3 cm proximal to the line of the wrist joint in the “snuffbox” area and 5–7 ml of a 1–2% anesthetic solution is infiltrated subcutaneously, between the tendons of the long and short extensor pollicis.

Complications

Possible complications when performing a blockade are puncture damage to the saphenous veins, intra-stem injection of the drug into the nerve with subsequent neuropathy, an allergic reaction to an anesthetic (1 case in 50 thousand) and a general systemic reaction of the body when the solution enters a blood vessel, which can be avoided by performing an aspiration test ( pull the syringe piston towards itself) before administering the local anesthetic.

conclusions

Since the hand has a complex structure, when carrying out aesthetic procedures in this area, it is very important for specialists to know the features of the anatomy, an accurate understanding of absolute contraindications and the most dangerous areas when performing manipulations.