Where does tetanus collide?

In muscle physiology, tetanus is the sustained, smooth contraction a muscle produces when it is stimulated so rapidly that individual twitches fuse and their forces add together; at high enough stimulus rates the ripples vanish entirely into a fused tetanus that reaches the muscle's maximal tension. Rack and Westbury's 1969 The effects of length and stimulus rate on tension in the isometric cat soleus muscle mapped how tension rises with stimulation frequency and muscle length toward this fused plateau. The referent is a mechanical state of a muscle driven by temporal summation, measured as force at a given firing rate, and it has nothing to do with the infectious disease beyond the shared Greek root for stiffness.[1]

Unit

The fused tension a muscle reaches as stimulus frequency rises

Recovery means

Tension relaxes once high-frequency stimulation stops

Measured by

Measured as isometric force across stimulation frequencies, from unfused twitches to a fused tetanic plateau

In clinical medicine, tetanus is an acute disease caused by the neurotoxin tetanospasmin from Clostridium tetani, which blocks inhibitory neurotransmission in the spinal cord and brainstem and so releases muscles into violent, sustained spasms, the rigidity and lockjaw that give the illness its name. Cook, Protheroe, and Handel's 2001 Tetanus: a review of the literature summarises its toxin mechanism, clinical course, and management. The referent is an infectious neurological disease defined by toxin-driven spasm and prevented by vaccination, a different construct from the laboratory muscle state and joined to it only by the word for stiffening.[2]

Unit

The presence and severity of toxin-induced muscular spasm and rigidity

Recovery means

Recovery follows toxin clearance and supportive care as unbound toxin is cleared and new nerve terminals form

Measured by

Diagnosed clinically from characteristic spasms and history, with severity graded by clinical scales