Fernando Valenzuela-Aedo; Carlos Torres-Villar; Víctor Ravelo; Rodrigo Muñoz-Cofré & Mariano del Sol

Striated muscle is an organized tissue that utilizes chemical energy to perform physical work, generated through muscle contraction. Proper muscle tone is essential for efficient movement and basic bodily functions. Clinical practice categorizes muscle tone alterations as hypertonia, an increase in tone in skeletal and/or smooth muscles, and hypotonia or flaccidity, a decrease in skeletal muscle tone. These terms are widely used in rehabilitation to denote decreased muscle tone. This study examined the etymological origins of the terms Hypotonia and Flaccidity and their respective definitions. Etymological research utilized the Diccionario Médico- biológico, histórico y etimológico and Diccionario Latino-Español Español-Latino. Spanish definitions were sourced in Diccionario de Términos Médicos de La Real Academia de Medicina de España; Diccionario de la Lengua española; Diccionario Panhispánico de Términos Médicos; Biblioteca Nacional Médica and Biblioteca Virtual de Salud de Centro Latinoamericano y del Caribe. The clinical use of these terms was assessed through neurology articles per authors' criteria. Consequently, Hypotonia is deemed the more suitable term for describing decreased muscle tone in rehabilitation contexts. Depending on the lesion's origin, terms like Central Hypotonia and Peripheral Hypotonia may be used when structures associated with the central or peripheral nervous systems are affected, respectively. It is suggested that these terms be adopted in clinical practice and teaching when addressing alterations in central or peripheral nervous systems resulting in reduced muscle tone.

KEY WORDS: Hypotonia; Flaccidity; Nervous system; Etymology; Rehabilitation.

VALENZUELA-AEDO, F.; TORRES-VILLAR, C.; RAVELO, V.; MUÑOZ-COFRÉ, R. & DEL SOL, M. Hypotonia or flaccidity in rehabilitation? A recommendation from the etymological origin. Int. J. Morphol., 42(4):1029-1032, 2024.