Edge loop

In organic modeling, edge loops play a vital role in proper deformation of the mesh.

[2] A properly modeled mesh will take into careful consideration the placement and termination of these edge loops.

Generally, edge loops follow the structure and contour of the muscles that they mimic.

An edge loop closely mimics how real muscles work, and if built correctly, provides control over contour and silhouette in any position.

"Edge loop" was first coined as a modelling term in 1999 by 3D artist Bay Raitt, in an article called Digital sculpting techniques for 3D Design magazine.