What does hypertonia mean?
Hypertonia is a medical term for abnormally increased muscle tone. It describes muscles that remain unusually tense and resist being moved or stretched, often making a limb feel stiff and making movement difficult. The condition can occur in several neurological and medical contexts, including stroke, cerebral palsy, multiple sclerosis, and brain injury. Hypertonia is related to spasticity, but the terms are not interchangeable: spasticity refers to a particular velocity-dependent increase in resistance caused by exaggerated stretch reflexes, whereas hypertonia is the broader clinical description of excessive muscle tone. The opposite condition is hypotonia, in which muscle tone is reduced. In clinical records and discussions of rehabilitation, hypertonia commonly refers to persistent stiffness that may affect posture, movement, comfort, and the ability to perform everyday tasks.
nounA state of abnormally increased muscle tone, in which muscles resist passive movement more than usual. It may result from neurological injury, disease, or other medical conditions and is often discussed in relation to spasticity.
- A clinical condition characterized by excessive muscle tone and increased resistance to passive movement.
"The neurologist explained that the child's hypertonia was causing persistent stiffness in both legs."
"Physical therapy was introduced to reduce the patient's hypertonia and improve mobility."
"The report notes persistent hypertonia in the right arm following the stroke."
The plural is possible but uncommon; in medical writing, the singular “hypertonia” is often used for the condition generally, while individual affected limbs or muscle groups may be discussed in the plural.
"The report describes hypertonias affecting both lower limbs."
Hypertonia names the stiff, resistant state of a muscle; spasticity is one specific neurological mechanism that can produce it.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does hypertonia come from?
The word combines the Greek prefix hyper-, meaning “over” or “excessive,” with -tonia, derived from Greek tonos, meaning “tension” or “tone.” Its development followed the medical use of terms such as hypertonic and hypotonic to describe increased and reduced muscle tension. The same Greek root is reflected in English words including tone, tonic, tonus, and tonicity.
Related word forms
How hypertonia is actually used
This is primarily a medical term, especially used in neurology, rehabilitation, and physiotherapy. It describes a clinical sign or condition and is less common in general conversation than “stiffness” or “muscle tightness.”
Easily confused with hypertonia
Hypertonia means abnormally increased muscle tone, whereas hypotonia means abnormally reduced muscle tone and reduced resistance to passive movement.