Basic Knot

The Anatomy of a Square Knot

Wayne W. LaMorte, M.D., Ph.D., M.P.H.

Photography by Michael J. LaMorte


basicknot5

A square knot consists of two “throws”.


basic knot 1

Throws are constructed by crossing the ends of the suture to form a loop and then wrapping one end of the suture around the other.
Here, the short end has been crossed over the long end to form a loop.


Basic Knot 2

The short end has been wrapped around the long end by passing it under the long end and up through the loop to complete the first “throw”.


Basic Knot 3

The loop for the second throw is initiated by once again crossing the short end over the long strand from right to left. [NOTE: A “granny knot” results if the short end crosses above the long end for one loop and below it for the other.]


Basic Knot 4

The short end has been wrapped around the long end a second time by passing it under the long end and up through the loop to complete the second “throw”.


Basic Knot 5

The knot has now been tightened, and the result is a square knot.
Each of the techniques for tying square knots (one hand tie, two hand tie, or instrument tie) achieves the same steps illustrated here.