A device for measurement of radius of curvature of obstetric forceps.

Details of the design of obstetric forceps are important to ensure that they can be used safely for mother and baby. One of the most important measurements is the radius of the cephalic curve of the blades since if this is inappropriate there will be a poor grip on the baby's head and risk of slippage, superficial injury or even intracranial haemorrhage and brain damage because of undue compression. Because of the complex design of the forceps blades, which have a pelvic curve as well as a cephalic curve and a fenestra, the radius of the cephalic curve is difficult to measure. A device was designed to facilitate this measurement and was found to be accurate and reliable in use. This was the first stage in the study to assess the suitability for modern practice of instruments designed many years ago.