Neck and back pain frequently arises from the small joints in the spine called zygapophysial or facet joints. The most common cause is osteoarthritis. Each facet joint has two nerves (medial branch nerves) that can transmit pain information to the brain. Medial branch blocks are used to determine if the facet joint in the source of a person’s pain. Local anesthetic is used to freeze the two nerves. If pain is relieved it confirms that the joint was the source of a person’s pain. Multiple injections can be performed to identify which joint or joints are painful. Local anesthetic only lasts for hours and the pain will return after the local anesthetic wears off. This is a diagnostic block. Cortisone can be injected into the painful joints to try to provide more long-term pain relief. This is referred to as a therapeutic injection.