They can also be described according to the path of the needle. Most epidural steroid injections are placed between the lamina, known as interlaminar epidural steroid injections. The lamina are portions of the bones on the back side of the spine that are arranged like shingles . The needle is aimed upwards toward the head and passes between two adjacent lamina. Another type of injection is a transforaminal steroid injection. In this case the needle passes along the course of the nerve and enters the spine from a more diagonal direction.