The common knot used in surgery is the square knot. A half hitch is one revolution of one end of a ligature around the other. The revolution is made in two half-revolutions. The second half of the revolution is done differently by laymen and surgeons. Laymen poke the suture through the loop.
Surgeons poke a finger or fingers through the loop, then grasp and bring the free end through.
Control is thereby maintained by keeping hold of the free end during the manipulation. In proceeding through the following knot-tying maneuvers, stay aware that you are merely revolving the free segment a single turn around the fixed one. Many righthanded surgeons tie left-handed, grasping the free end with the left hand. An advantage of left-handed tying, besides the manipulation being done with the dominant right hand, is that a surgeon tying his own knots during suturing does not need. The two-handed knot has the advantage of the greatest precision in maintaining constant tension on the suture during the tying process.