Constitutive mechanical properties of carpal tunnel soft tissue structures

Carpal tunnel syndrome is a frequently encountered chronic peripheral nerve entrapment disorder caused by mechanical insult to the median nerve, which may occur from impingement by the surrounding digital flexor tendons and the tunnel boundaries. Anatomic finite element models of the carpal tunnel provide a method to evaluate the potential contact stresses that may develop on the median nerve between the digital flexor tendons and tunnel boundaries. Realistic finite element simulations are dependent upon the use of physiologically accurate material properties. The purpose of this work was to ascertain material properties for the digital flexor tendons, median nerve and transverse carpal ligament to inform finite element simulations. The compressive mechanical behavior of the digital flexor tendons, median nerve and transverse carpal ligament was characterized under functionally relevant axial tensile loads. These properties can now be implemented into full scale finite element models of the carpal tunnel to evaluate the mechanism of insult to the median nerve leading to the development of carpal tunnel syndrome.