Measuring first ray mobility with a new device

First ray hypermobility has been linked to many abnormal conditions in the foot. First metatarsal vertical displacement is proportional to the measure ment of first ray dorsiflexion. A new device that measures first ray mobili ty has been built and tested. The device applies a dorsiflexing force to th e head of the first metatarsal and measures the amount of vertical displace ment that results. The design and instrumentation of the device is describe d. A safe and reliable testing procedure for measuring maximal first ray di splacement is discussed. Clinicians could use this measure when selecting t reatment options for patients who suffer foot pathologies resulting from fa ulty mechanics of the first ray. (C) 1999 by the American Congress of Rehab ilitation Medicine and the American Academy of Physical Medicine and Rehabi litation.