Taking the content of the previous posts as a whole , it seems quite possible that the transverse arch of the foot provides the majority of the foot stiffness required for energy efficient gait . It also seems likely that the distal transverse arch becomes more pronounced as the forefoot is loaded and the toes become more dorsiflexed .
With regard to maintaining foot structure then , perhaps the primary role of the intrinsic muscles of the foot is to help maintain the integrity of the transverse arch of the foot and not the longitudinal arch .
For example the oblique head of the adductor hallucis could be viewed as a torsion resistant cross strut of the transverse system .

Gerry

Gerrard Farrell

Glasgow