Knots are used for a wide variety of purposes. For example, in surgery you cannot do without them. The surgical knot, known for its special strength, is actually a modification of the straight knot, where the first loop makes two turns for greater strength.
To make a surgical knot, first fix the sutures in their original position. Cross their free ends and hold them with the thumb and forefinger of both hands.
Cross the threads again and place the third finger (middle) of your right hand over the thread that this hand is holding. Place the thread held by your left hand on the nail of your third finger.
Now place this finger behind the thread that your left hand continues to hold. Pass the thread through the loop and straighten your finger. Now press the free end of this thread with your thumb against the palmar surface of the middle finger. Hold your index finger over the thread.
Pull the threads in opposite directions, move the knot slightly with the index fingers of both hands. Now tie the second knot as described, but use your other hand. The principle of the surgical knot is that the first two semi-knots do not allow the two ends of the thread to disperse in different directions, while another semi-knot is knitted, on top of the existing ones.
The surgical knot can also be useful in fishing, when you need, for example, to tie a leash to a fishing line. Anglers also call such a loop an end loop or a leash loop.
First fold the line and leash parallel to each other. Keep in mind that they should touch at least 15-20 cm in length. Tie a simple knot and pass the entire leash through the loop.
Do not tighten the knot and pass the end of the line with the leader through the loop again. Hold the leash and line on both sides. The knot can now be tightened.