Ultrasound anatomy in the normal neonatal and infant foot: an anatomic introduction to ultrasound assessment of foot deformities.

The aim of this study was to establish guidelines for US assessment of the talo-crural, the talo-navicular and the calcaneo-cuboid joints during the first year of life, which could serve as a reference while studying foot deformities. The feet of 54 healthy children were examined at birth and at the age of 4, 7 and 12 months by using three easily defined and reproducible US projections. With a medial projection the relation of the navicular in relation to the medial malleolus and the head of the talus was studied. A lateral projection revealed the calcaneo-cuboid relationship and a dorsal projection the talo-navicular alignment in the sagittal plane. Normal values for measurements of these cartilaginous relationships were established for the different age groups. Intra- and inter-observer reliability was assessed and found to be acceptable ( r=0.53-0.90, Pearson correlation coefficient). With US it is possible to obtain reproducible planes of investigation that give reliable information about the talo-crural, the talo-navicular and the calcaneo-cuboid relationships during the first year of life.