Magnetic Resonance Imaging of Velar Muscle Tissue Distribution in Healthy Adults

Objectives: To examine muscle tissue distribution along the length of the velum in living individuals using magnetic resonance imaging (MRI). Design: Using the three-dimensional MRI data acquired from 10 normal white adults, two area measures including the muscular area and the total velar area were obtained from 10 oblique slices running perpendicular to velar length. A polynomial regression analysis was performed where the proportion of the muscular to the total velar area was regressed on the slice numbers running along the length of the velum. Results: The proportion of the muscular to total velar area increased from the anterior section of the velum, reaching a maximum (33.24%) in the midsection, and decreasing in the posterior section of the velum. A third-order (cubic) polynomial function that best illustrated the proportional data (R-2 = .47) was derived. Conclusions: The present study demonstrated that MRI is a viable tool to examine the muscle tissue distribution of the velum in living individuals. Although the overall pattern in the muscle tissue distribution of the healthy velum was similar to that reported in previous literature based on cadaver specimens, the participants in the present study appeared to have greater muscular proportion of the velum. The muscular proportion measure derived from the healthy living individuals can be used as an additional parameter accounting for sufficient intravelar muscle mass for future studies.