Epineurium is a protective layer of connective tissue that surrounds a nerve. It is the outermost layer of a nerve and provides structural support, helping to maintain the integrity of the nerve fibers within. This layer contains blood vessels and helps to nourish the nerve, ensuring it functions properly. In addition to providing protection, the epineurium plays a role in the overall organization of the nerve. It encases bundles of nerve fibers, known as fascicles, which are further surrounded by another layer called perineurium. Together, these layers help to facilitate the transmission of electrical signals throughout the nervous system.