The shank of a pipe protrudes directly from the bowl, connects to the stem, and is typically carved from the same piece of briar (or meerschaum).  Great care is taken when carving the shank, since it is part of the bowl and its grain and form must compliment the pipe.   A well carved shank will be perfectly aligned with the bowl and stem: it will not curve left or right, unless intended.  Additionally, the shank is the weakest part of the pipe since it is thin and has an air hole drilled through it.  Shanks come in a variety of shapes, typically chosen to compliment the design of the pipe.