The early Egyptians noted that, without a plumb line as a reference, larger structures could not be built. The concept of the plumb line can be translated into an imaginary line to assist in navigating the hand surgery jungle-from indications and contraindication of procedures, to safety checks preoperatively and postoperatively, determining pain prescription guidelines for patients, and for billing and ethical decision making. We often reference intramedullary alignment, coronal alignment, and anatomic references to properly make our osteotomy cuts, place arthroplasty components, and reduce fractures. All permission requests for this image should be made to the copyright holder.Īs surgeons, we understand the need for a reliable and accurate reference or a “plumb line,” in order to execute the procedures correctly. Copyright Mayo Foundation, Rochester, MN. Taken with permission of the Mayo Foundation, copyright 2018. The vertical (A) and horizontal (B) plumb line tools. FIGURE 1:Īncient Egyptian use of the plumb line. This simple tool consistently and accurately defined horizontal and vertical planes and allowed for the complex construction of buildings, canals, and pyramids, which have endured for centuries. If the plumb line bisected the crossbar of the “A,” it was horizontal. The plumb line was attached to the tip of an “A” frame, and the legs of the “A” were placed on a surface ( Fig. The backbone of the “F” was placed against a wall, and the wall was determined to be perfectly vertical, when the plumb line touched the middle outerboard part of the middle of the “F.” The Egyptians also used the plumb line to determine perfect horizontal reference lines as well. 1 The tool was in the shape of an “F,” with the plumb line suspended, from the upper outboard part of the F ( Fig. The reproducible and constant vertical reference line created by this construct is known as the “plumb line.” It is called a “plumb” line after the lead weight (Latin for lead is “plumbum”) from which the line was historically suspended.Įarly use of the plumb line was recorded nearly 4000 years ago during ancient Egyptian times. In modern times, the lead was replaced by a brass conical cylinder with a point at the bottom. The suspended weight in ancient times was probably a stone and was replaced by lead in medieval times, as it was dense, heavy, and resisted movement from the wind. Some bobs have pointed tips that can be bent by repeated use or abuse if the point on yours is bent or out of alignment, replace it.A plumb line is a vertical line that is created from a string that has a suspended weight. Excavation and foundation contractors rely upon the plumb line, and constructing a chimney the tool can indicate whether a flue is running true vertical or veering off plumb. Surveyors sometimes use plumb bobs for lining up points or transferring them. The plumb line in one place can be used to sight an object in another - a pipe, for example - for plumb. Once it is hung and still, the top and bottom points can be marked and used as guides. For example, you can locate fixtures or decorations in relation to an object or surface below (or above) using the plumb line. A spirit level will also accomplish those tasks, but some jobs are much more easily done using the tool. The plumb bob is useful in establishing vertical for a wall in construction or a doorjamb when hanging a door. (Note that the line must be hanging free to get an accurate reading.) The weight, or bob, is then allowed to swing freely when it stops, the point of the bob is precisely below the point at which the string is fixed above. To use the tool, the string is fixed at the point to be plumbed.
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