## 4 Discussion  
The aim of this study was to investigate the difference in the structure of the transverse arch of the foot between women with and without HV deformity and to understand the effects of loading. Our results showed widening of TAL in the With-HV group compared to that in the Without-HV group, and a slight elevation in TAH in the With-HV group compared to that in the Without-HV group in sitting and standing positions; however, similar results were observed for TAH in the 90% W.S. position. As the load increased, both groups showed widening in TAL and compression in TAH. The differences in TAL between individuals with and without HV may be due to the extensibility of the ligaments acting on the transverse arch. [PERSON] et al. [20] studied the tensile strength of the deep transverse metatarsal ligament (DTML), a ligament that runs and indirectly connects the metatarsal heads and acts as their stabilizer [21; 22; 23]. They compared the extensibility of the DTML  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Without-HV (n = 260)**} & \multicolumn{3}{c}{**With-HV (n = 118)**} \\ \hline  & **Sitting** & **Standing** & **90\% W.S. ** & **Sitting** & **Standing** & **90\% W.S. ** \\ \hline TAL (mm) & 67.8 \(\pm\) 3.9 & 69.2 \(\pm\) 4.4 \({}^{\dagger}\) & 69.8 \(\pm\) 4.4 \({}^{\ddagger}\) & 69.5 \(\pm\) 4.0 \({}^{\lx@sectionsign}\) & 71.4 \(\pm\) 4.2 \({}^{\lx@sectionsign}\)* & 71.4 \(\pm\) 4.2 \({}^{\lx@sectionsign}\)* \\ MS\(-\)LS Length (mm) & 12.2 \(\pm\) 1.8 & 12.6 \(\pm\) 2.1 & 12.6 \(\pm\) 2.1 & 12.1 \(\pm\) 2.0 & 12.2 \(\pm\) 1.8 & 12.3 \(\pm\) 2.0 \\ LS\(-\)2 MTH Length (mm) & 14.0 \(\pm\) 2.4 & 14.0 \(\pm\) 2.6 & 14.3 \(\pm\) 2.5 & 14.4 \(\pm\) 2.7 & 14.9 \({}^{\lx@sectionsign}\) 2.8 & 14.6 \(\pm\) 2.5 \\
2\(-\)3 MTH Length (mm) & 12.7 \(\pm\) 1.7 & 13.2 \(\pm\) 1.9 \({}^{\dagger}\) & 13.2 \(\pm\) 1.9 \({}^{\dagger}\) & 13.6 \(\pm\) 1.7 \({}^{\lx@sectionsign}\) & 14.3 \(\pm\) 2.2 \({}^{\lx@sectionsign}\)* & 14.4 \(\pm\) 1.9 \({}^{\lx@sectionsign}\)* \\
3\(-\)4 MTH Length (mm) & 13.3 \(\pm\) 1.8 & 13.8 \(\pm\) 1.9 \({}^{\dagger}\) & 13.8 \(\pm\) 2.1 \({}^{\dagger}\) & 13.9 \(\pm\) 1.6 \({}^{\lx@sectionsign}\) & 14.1 \(\pm\) 2.0 & 14.2 \(\pm\) 2.2 \\
4\(-\)5 MTH Length (mm) & 16.6 \(\pm\) 2.1 & 16.8 \(\pm\) 2.2 & 17.0 \(\pm\) 2.0 & 16.6 \(\pm\) 1.9 & 17.2 \(\pm\) 2.2 & 17.3 \(\pm\) 2.1 \({}^{\lx@parbetween women with HV and controls, and demonstrated that the tensile strength of the DTML was inferior in women with HV compared to that in controls, indicating that the DTML is indeed stretched in HV deformity [20], allowing the MTHs to separate from each other. TAL also increased with an increase in load in both groups. The widening of the transverse arch in both groups is in accordance with the fact that the transverse arch splays and drops during gait, as it flattens when receiving loads [19]. Another study also reported that the metatarsal abducted at 50% body weight load, and these movements increased at 100% body weight load [24]. These previously proved findings explain the widening of TAL and the lengths between the metatarsal heads. Our results showed higher TAH in the With-HV group than in the Without-HV group in sitting and standing positions. In the 90% W.S. position, however, TAH was similar between both groups. These results were unexpected as we had hypothesized that the transverse arch of the With-HV group would have a lower TAH. This result could be attributed to a protective mechanism that is activated in HV deformity to maintain the arch and enable propulsion. We suggest that the intrinsic muscles of the foot act on transverse arch, similar to the mechanism acting on the MLA. Previous studies have showed that under loading conditions during gait, the MLA compresses and absorbs the energy loads and then transmits it as propulsion forces [24; 25; 26]. To protect the MLA from collapsing completely, the intrinsic muscles of the foot activate a dynamic feedback-response system to assist in its stability, support, stiffness, and propulsion [24; 27].