Used within Orthopedic surgery, there has been some exploration of the use of the tuning fork, smallest frequency 128 Hz, to assist the assessment of injuries where bone fracture is suspected. The tuning fork is toned on the suspected bone with fracture and toned progressively closer to suspected area of fracture. If there is a fracture, the periosteum of the bone will vibrate and fire nociceptors (pain receptors) causing a local sharp pain. This is a positive indication of a fracture that the practitioner is indicated to refer for medical x-ray. Lower-pitched ones are also used to check vibration sense as part of the examination of the peripheral nervous system.