## 4 Discussion  
The results show that compression of the median nerve occurs faster during wrist flexion than during the wrist extension or the fingers flexion, which is consistent with experimental studies [26]. Extension and flexion of the wrist is a typical movement of the Phalen test, which is used to diagnose carpal tunnel syndrome. The patient flexes and extends the wrist 90 degrees and the median nerve experiences compression [27]. In our studies, the maximum flexion/extension angle was 17.5 degrees. Further studies are required to obtain 90-degree hand flexion/extension results. The observed pressure on the median nerve decreased in the two-step simulation (Figure 5, case 3) indicating opposite loading areas during wrist extension and finger flexion sequences. It is assumed that with an increase in the phalangeal angle of finger flexion after a slight decrease, the compression will further increase. However, the existence of movements that reduce median nerve compression can help to create simulators and exercises for decompression. This study focused on finite element modeling of the finger, carpal bone, and tendon system, and determined the effect of tendon movement on median nerve compression. However, a comparison with experimental results is required to validate the data obtained. Nevertheless, determining the pressure inside the carpal tunnel experimentally is problematic due to the tendons and median nerve being enclosed within the carpal tunnel, and any opening of the tunnel or penetration will result in loss of the enclosed space effect and the pressure measurement results will most likely be incorrect. This assumption is a prerequisite for mathematical modeling of carpal tunnel pressure determination compared to experimental approaches. Nevertheless, there are some indirect data in the literature in which the results can be compared. The pressure values in the median nerve obtained in this study coincide with the values obtained experimentally by [PERSON] at. al. 1983 [28]. [PERSON] at. al. determined the endoneurial fluid pressure in the carpal tunnel over time with an external carpal tunnel load of 30 and 80 mmHg. Normal endoneurial fluid pressure in their study was in the range from 1 to 3 cm H\({}_{2}\)O (from \(\sim\)100 to 300 Pa). It can be assumed that the endoneurial fluid applies a similar pressure to the median nerve. In this case, the results of finite-element modeling agree with the experimental data. The median nerve stressed obtained in this study were lower than similar results in other experimental  
Figure 8: Distribution of directed movements X and Y by tendon (1) Thumb, 2.1\(-\)superficial flexor index finger, 2.2\(-\)deep flexor index finger, 3.1\(-\)superficial flexor middle finger, 3.2\(-\)deep flexor middle finger, 4.1\(-\)superficial flexor ring finger, 4.2\(-\)deep flexor ring finger, 5.1\(-\)superficial flexor pinky, 5.2\(-\)deep flexor pinky). (**a**) Coordinate system, (**b**) case 1 (finger flexion), (**c**) case 2 (wrist extension), (**d**) case 4 (wrist flexion). studies [26; 28; 29; 30; 31]. However, in such studies, the pressure was measured indirectly and with flexion and extension of the hand up to 90 degrees. In this study, flexion was simulated at 17.5 degrees and extension at 30 degrees. In this case, the results are closer to the neutral position of the wrist than to the maximum flexion or extension to 90 degrees. Comparison of the results obtained using the finite element method with the neutral position of the wrist obtained experimentally shows a good agreement, as in Table 4.  
The experimental method of determination of intercarpal pressure usually consists in using a catheter that measures hydrostatic pressure. Finite-element modeling assumes zero pressure at the initial moment of time modeling, but with a neutral wrist the nerve is under slight pressure. This was not taken into account in our work and may be investigate in the near future. However, the stress values obtained in this work can be added to the stress values in the neutral position.