The taeniae coli are the three outer muscular bands of the cecum, ascending colon, transverse colon, and descending colon.
The taeniae coli converge at the base of the appendix in the cecum where they form a complete longitudinal layer. In the ascending and descending colon, the bands are located anteriorly, posteromedially and posterolaterally. Due to the rotation of the colon with the transverse colon, the taeniae coli are located posteriorly, anterosuperiorly and anteroinferiorly.
In the sigmoid colon, the taeniae coli gradually broaden to form anterior and posterior layers which fuse laterally, to form the longitudinal layer of the rectum.
In an appendectomy, if the appendix is not immediately obvious, the taeniae coli can be used as a guide to find the appendix where the merge at it's base.