Pressure tolerance over muscles and bones in normal subjects.

Pressure tolerance (PTo) is the maximum force a person can tolerate without excessive effort. Pressure threshold (PT) is the minimum force that induces discomfort or pain. Both measures have proven to be extremely useful in evaluating patients with chronic pain. This study documents PTo in 50 healthy, pain-free subjects. Measurements were taken with a rubber disc of 1cm2 attached to a pressure gauge calibrated in units of force, (newtons/cm2). Measurements were taken over two muscle sites: supraspinatus and deltoid, and over two bone sites: thumb and midtibia; measurements were taken on each subject's right and left sides. Pressure over the skin was gradually increased by 10 newtons/sec until the subject examined said "stop." Normal values for PTo were established for men and women; PTo is slightly higher in men. Statistical analysis failed to demonstrate significant difference in PTo over corresponding opposite sides. Identical contralateral findings prove the excellent reproducibility and validity of pressure tolerance measurements. Clinical applications include: generalized myopathy is considered when muscle PTo is lower than bone (reversal of normal relation). The condition is caused usually by treatable endocrine deficiency. Low pain tolerance (hyperalgesic syndrome) is manifested by decreased PTo over both muscles and bones. Special therapeutic approaches are necessary for these patients. Functional disorders are characterized by lower PTo than in organic disease.