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.
A nerve root block is an injection of local anesthetic and sometimes a steroid under the directed vision of an x-ray machine (C-Arm) into the areas where the nerve root exits the spinal column. A nerve root block (injection) follows the path of a single nerve to block pain emitted into an arm, leg or back.