opening) is the distance between the central incisors when the mouth is fully open.
Average MIO for adults is approx. 50mm. By measuring MIO, a therapist can determine
if a patient is WNL or has trismus. ROM (Range-of-Motion) is the maximum distance
An often neglected burden of HNC survivorship is that on the psychological effects of head and neck cancer on both the patients and caregivers. How can we, the providers, help?
Reconfirmed!! New research reinforces the correlation between radiation dose to the masseter and pterygoid muscles with the development of trismus.
The study “Radiation dose to the masseter and medial pterygoid muscle in relation to trismus after chemoradiotherapy for advanced head and neck cancer” stresses the impact of radiation dose on the ipsilateral masseter muscle and the ipsilateral medial pterygoid muscle in head and neck cancer patients. A meaningful analysis of data was conducted across 83 patients treated for advanced squamous cell carcinoma of the head and neck. These patients participated in a preventive exercise program for mouth opening and MIO measurements were compared. The study concluded that radiation dose on the ipsilateral masseter muscle and ipsilateral medial pterygoid muscle is predictive for trismus.