The Root’s Test, named after Merton Root DPM, checked for hypermobility of the first ray.
This is performed to evaluate first ray (metatarsal and medial cuneiform) hypermobility in the sagittal plane. (Fig 1) Step 1: place left thumb & index finger on the head of the 1st metatarsal bone. Step 2: place the thumb and index finger on head of metatarsal 2,3 and 4 with your right hand. Step 3; move ONLY the 1st metatarsal head and take it through dorsal and plantar excursion. A normal total excursion is 10 mm (5mm dorsal, 5mm plantar), if excursion is more than (>10mm) than it is considered a hypermobile first ray.
Root ML, Orien WP, Weed JH. Normal and abnormal function of the foot, Los Angeles 1977, Clinical Biomechanics Corp