1 A ligand is any molecule that binds to a specific site on a protein or other molecule. In this case, the estrogen hormone 17-beta-estradiol is the ligand, and the estrogen receptor is the protein.  Binding turns on, or activates, a hormone receptor.
A femoral nerve block is a type of regional anesthesia in which the femoral nerve, located in the groin area, is deadened to allow surgery in the leg or knee area.
Nerve Blocks. A nerve block is an injection to decrease inflammation or turn off a pain signal along a specific distribution of nerve. Imaging guidance may be used to place the needle in the right location for maximum benefit.