What does hypertonicity mean?
Hypertonicity means an abnormally increased degree of tension or firmness. Its best-known medical use concerns muscles that remain unusually tight, contract excessively, or cannot relax normally; the condition may occur in disorders affecting the nervous system and muscles. In physiology and chemistry, hypertonicity instead describes a solution whose solute concentration and osmotic pressure are greater than those of a reference solution or surrounding fluid. A hypertonic environment causes water to move toward the more concentrated solution through osmosis, which is important in cellular biology, intravenous treatment, and resuscitation. The term can also be used more generally for any state of excessive tension. It is therefore related in meaning to hypertonic, while remaining distinct from the noun hypertonia, which most often refers specifically to a clinical condition involving increased muscle tone.
An abnormally increased state of muscle tone or tension, or the more general condition of being excessively tense.
"The treatment was intended to ease the hypertonicity affecting her leg muscles."
This is a technical medical term, especially in neurology and rehabilitation.
The property of a solution having a higher solute concentration and osmotic pressure than another solution or biological fluid.
"The saline solution was adjusted to prevent excessive hypertonicity in the patient's circulation."
Common in physiology, medicine, and laboratory contexts; the comparison solution or fluid should be clear from context.
The plural is grammatically regular but rarely needed, because references are normally to the condition rather than to separate instances.
"The study compared patterns of muscle hypertonicities in the two clinical groups."
A hypertonic solution draws water toward its greater concentration, while the same term in neurology describes muscles that cannot fully relax.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does hypertonicity come from?
The word was formed through the combining form hyper-, from Greek huper, meaning “over” or “beyond,” together with tonicity, which derives from tonic and ultimately from Greek tonikos, relating to tension or stretching. The prefix hyper- indicates an excessive degree of this quality. English cognates include hypertonic and hypertension, although the latter originally developed with a different emphasis in medical usage.
Related word forms
How hypertonicity is actually used
In clinical neurology, the term is technical and normally refers to increased resting muscle tone rather than ordinary muscular tension. In physiology and medicine, its use for osmotic concentration is especially common in descriptions of fluids, treatments, and cellular environments.
Easily confused with hypertonicity
Hypertonia usually names the clinical condition of excessive muscle tone, whereas hypertonicity can denote either the underlying state of increased tension or, in a chemical context, a solution's greater osmotic pressure.