Study of Topography of Stylomastoid Foramen With Respect to Nearby Landmarks to Carry Out Facial Nerve Block With Minimum Complications.

Nadbath facial nerve block is the most common procedure to anesthetize the facial nerve at stylomastoid foramen in intraocular surgeries, but it is associated with complications. Also, this foramen exhibits ethnic and racial variations with regard to its location. There is scanty literature describing the topographical location of this foramen. So, the study is carried out. The purpose of the study is to describe the topography of stylomastoid foramen from the surrounding landmarks so that Nadbath facial nerve block can be performed with minimum complications. The study was conducted using 80 adult dry skulls of unknown age and sex, and the distance of this foramen was measured from the tip, upper end, and lower end of the anterior border of the mastoid process and jugular foramen. The statistical analysis consisting of mean, SD, median, range mode, and t test was calculated. Mean distances of stylomastoid foramen from the upper end, the lower end of anterior border and tip of mastoid process and jugular foramen on right side were 1.5±0.16, 1.02±0.09, 0.84±0.09, and 0.49±0.06 cm and those on left side were 1.5±0.16, 1.02±0.09, 0.84±0.09, and 0.5±0.06 cm, respectively. The mode of these distances was 1.5, 1, 0.8, and 0.5, both on the right and left sides. The topographic information about stylomastoid foramen given in this study is useful to anesthetists to carry out Nadbath facial nerve block successfully with minimum complications.