[Form and structure of the metatarsal head arch in adults. Ultrasonographic and podometric studies].

Ultrasonic measurements (n = 172) and plantar pressure investigations (n = 119) are performed on the forefeet of healthy adults, in order to constitute a correlation between shape and function of the anterior metatarsal arch. The thickness of the sole of the foot has its maximum beneath the 2nd metatarsal head and its minimum beneath the 1st and 5th ray. The highest pressure values are found at the 2nd and 3rd metatarsal head. It is concluded that despite the arch like configuration of the forefoot there is no structural arch function. The biological principle of adequate padding of pressure points results-depending on the load-in a different thickness of the soft tissues of the sole of the foot. The higher pressure under the central metatarsal heads is accompanied by thicker soft tissue pads and a more dorsal position of these rays.