神经外膜（Epineurium）是包覆神经周围的结缔组织之最外一层。神经外膜内包含了供应神经养分及氧气的纵行血管。神经外膜由脂肪组织与纤维胶原组织所组成。

• 神经束膜
• 神经内膜

The epineurium is the outermost layer of dense irregular connective tissue surrounding a peripheral nerve. It usually surrounds multiple nerve fascicles as well as blood vessels which supply the nerve. Smaller branches of these blood vessels penetrate into the perineurium. In addition to blood vessels which supply the nerve, lymphocytes and fibroblasts are also present and contribute to the production of collagen fibers that form the backbone of the epineurium. In addition to providing structural support, lymphocytes and fibroblasts also play a vital role in maintenance and repair of the surrounding tissues.