The procedure can be applied to any nerve epineurium. These electrodes are placed on the nerve and secured by suturing to the epineurium. It is present in the connective tissue of the endoneurium, perineurium, and epineurium. Fascicles are bound together in a common membrane, the epineurium. Finally, the entire nerve is wrapped in a layer of connective tissue called the epineurium. In fourth-degree injury, only the epineurium remain intact. A perineurium surrounds that and the outermost layer is considered the epineurium. The epineurium and perineurium remain intact, thus preventing the formation of stump neuroma. The epineurium is the outermost layer of dense irregular connective tissue surrounding a peripheral nerve.