Jaw Opening Decreases Window to the Deep Parotid Lobe.

To describe the relationship between jaw opening and access to the deep parotid window, we identified the following distances in 10 human skulls: symphysis to angle of mandible, mastoid tip to angle of mandible, angle of mandible to condylar process, and mastoid tip to condylar process. With the jaw closed and open, these distances were measured with 1 to 3 wooden blocks, each measuring 1 cm, between the upper and lower incisors. The triangular deep parotid area formed by the last 3 distances was calculated. A repeated measures analysis of variance showed a significant decrease in the deep parotid area with increasing interincisal distance ( P < .01). A generalized estimating equation model demonstrated a statistically significant decreasing area of the deep parotid window with increasing interincisal distance. These results suggest that nasal intubation may improve access to the parotid window.