Letter: Is Peripheral Nerve a Misnomer? A Critique of Commonly Used Terminology.

Abstract

To the Editor: Within medical education, the use of correct terminology is important to ensure accuracy and minimize any confusion to trainees. In general, educators frequently refer to peripheral nerves to separate these nerves from the cranial nerves. Although this is well intentioned, that distinction is inherently incorrect. More accurately, cranial nerves should be contrasted to spinal nerves by the distinction of their exiting location. This confusion is evident in some of the most well-renowned textbooks in our field. For example, Adams and Victor's Neurology textbook dedicates chapter 46 to Diseases of the peripheral nerves and chapter 47 to Diseases of the cranial nerves.1 Even Tinel,2 well-known for the Tinel sign, has a book called “Blessures des Nerfs” [Nerve Injuries, in French]; however, the subtitle states “Sémiologie des Lésions Nerveuses Péripheriques par Blessures de Guerre” [Semiology of Peripheral Nerve Lesions from War Injuries]. In the past several decades, nerve surgery has colloquially been named “peripheral nerve” surgery because many of the procedures conducted involve surgery on nerves that belong to the peripheral nervous system, meaning their ganglia outside of the central nervous system. Although well intentioned for delineation, the modern nerve surgeon frequently operates with a variety of cranial nerves as well including the spinal accessory nerve, hypoglossal nerve, and for a variety of procedures involving the spinal nerves. In addition, many “nerve surgeons” are routinely involved in facial nerve repair. Anatomically, the peripheral nervous system consists of cranial nerves, spinal nerves, and sympathetic nervous system while the central nervous system is the brain and spinal cord. The brain comprises the telencephalon (cerebral hemispheres), diencephalon (thalamus, hypothalamus, and epithalamus), mesencephalon (midbrain), metencephalon (pons and cerebellum), and myelencephalon (medulla oblongata).2 These may be “no brainers” but are important basic anatomic facts that we frequently forget unless prompted to give an anatomy lecture. When describing the peripheral nervous system, Arey3 states that “fibers converge into distinct cables called ‘nerves,’” which are arranged in pairs. Gray's anatomy uses the terms cranial nerves and spinal nerves and describes the peripheral nervous system as 12 pairs of cranial and 31 pairs of spinal nerves, occasionally lumped up as cerebrospinal nerves.4 Mackinnon,5 a well-respected nerve surgeon, named her book Surgery of the Peripheral Nerve in 1988. In 2015, she published another book: Nerve Surgery, likely realizing that these are simply “nerves” not peripheral.6 This is a trend that we would like to see continue. Kline and Hudson who trained most neurosurgeons operating on nerves in North America named their atlas “Atlas of Peripheral Nerve Surgery” while their textbook is simply called “Nerve Injuries.”7,8 We advocate for renaming societies such as American Society of Peripheral Nerves and Disorders of Spine and Peripheral Nerves to American Society of Nerves and Disorders of Spine and Nerves. Let us just call things what they anatomically are and not what everybody calls them. This will likely be faced by resistance, and it will take years to change the culture. The first book by the senior author was called “Anatomy and Exposure of Spinal Nerves” and the second book “Nerve Cases.”9,10 In conclusion, what is commonly referred to as “peripheral nerves” from an anatomic standpoint should be simply referred to as “nerves” and thus we suggest more that the more accurate terminology of “nerve surgery” rather than “peripheral nerve surgery” be used. By doing this, we gain an improved accuracy in our terminology and resultantly better medical education for future generations.