The Gasserian ganglion is a small collection of nerve cells and fibers found at the base of the skull. It has three nerve branches known as the Trigeminal Nerves. These three branches are responsible for sensation on the side of the face. The Gasserian ganglion or trigeminal ganglion injection is a brief, minimally invasive procedure that is performed using local anesthetic to inhibit the signals from going through those nerves in order to control facial pain. Sometimes steroid is also used for this procedure.