Pressure dynamics of the carpal tunnel and flexor compartment of the forearm.

Although carpal tunnel pressures have been observed to increase as a result of repetitive flexion and extension of the wrist, and forearm compartment pressures have been shown to rise during and after muscle activity, the relationship between those two observations has not been studied. The flexor compartments of five cadavers were perfused with saline to determine whether elevated pressure in the flexor compartment of the forearm is transmitted to the carpal tunnel. The pressure in the carpal tunnel after the infusion was significantly different from the pressure in the flexor compartment of the forearm. Furthermore, pressures recorded in the carpal tunnel at the conclusion of the study were not statistically different from the preinfusion pressures. While the carpal tunnel may appear to be an open compartment anatomically, it functions as a relatively closed compartment with respect to transfer of pressure from the flexor compartment of the forearm under conditions that mimic elevated tissue pressure.