Facial landmark-based localization of the parotid duct: a cadaveric study with ultrasonographic feasibility assessment

The parotid duct (Stensen’s duct) runs superficially across the midface and is often encountered during aesthetic or surgical procedures. Accurate knowledge of its spatial orientation is essential to avoid iatrogenic injury. This study aimed to define the spatial course of the parotid duct relative to facial surface landmarks to demonstrate the feasibility of ultrasonographic identification of these relationships in vivo. Thirty-two hemifaces from sixteen adult cadavers (15 Korean, 1 Caucasian; 9 males, 7 females; mean age 82 years) were dissected to trace the parotid duct from the gland to its penetration through the buccinator. The position of the duct was analyzed relative to (1) the tragus–mouth corner line, (2) the philtrum level (midpoint, upper one-third, or lower one-third), and (3) vertical lines through the canthi. High-resolution ultrasonography was performed in a single healthy volunteer to provide an in vivo feasibility demonstration of the cadaveric findings. At the anterior border of the masseter, the duct was located slightly superior to the tragus–mouth corner line in 84.4% of specimens, on the line in 3.1%, and below it in 12.5%, most of which possessed an accessory parotid gland. Horizontally, the duct aligned with the philtrum midpoint in 65.6%, with the upper one-third in 25.0%, and with the lower one-third in 9.4%. The buccinator penetration point was medial to the vertical line through the lateral canthus in 87.5%. Ultrasonography in a single healthy volunteer visually demonstrated the feasibility of identifying these anatomical relationships in vivo. The parotid duct follows a relatively reproducible course that may be estimated using established facial landmarks.