Kinnison Edmunds and Dr. Jonathan Wisco, Department of Physiology and Developmental Biology
Introduction
The goal of my project was to create a data-driven, three-dimensional map of the human trigeminal nerve from the trigeminal ganglion to the ends of its major pathways throughout the face and head. The purpose was to test conventional wisdom regarding the pathways of the trigeminal nerve and expose any inconsistencies between artistic representations and a data-driven mapping of the nerve. It was my hypothesis that by comparing my completed nerve map to the currently accepted anatomy literature, I will be able to challenge existing discrepancies and improve the validity of current anatomical representations.
Methodology
The mapping process consisted of the following phases:
(1) Selecting a manageable length of nerve, marking closely spaced segments with a marker, and recording caliper measurements of the width of the nerve at that particular point
a. Images were taken of each specimen before any other procedures were completed
b. A spreadsheet was developed to track the number of nerves, innervations, the caliper measurements, and the specimen number
c. A minimally invasive dissection technique was used to reflect tissue and expose desired nerve branches
d. Using a marker, points were made along each nerve branch to facilitate quick and neat MicroScribe capturing
(2) Creating the digital model of each specimen using the MicroScribe
a. First, drilled three screws into the bone structure of each specimen. These served as absolute reference points for calibrating the MicroScribe machine.
b. An outline was taken of each specimen in order to aid researchers in making visual connections between the actual specimen and the digital model
c. Capturing each marked point on each nerve branch using the MicroScribe tool
(3) Generating a 3-D model using animation software (AutoDesk Maya)
a. Each set of data points captured from the MicroScribe was exported to Maya
b. A procedure was developed and conducted for connecting, filling, and rendering each model
Results and Discussion
During a dissection early on in the course of my project, an anomaly was noted in the anatomy of the nerves passing between the sublingual gland and the gingiva of one particular specimen. There were several innervations that appeared to exist in our specimen that were not apparent in common anatomical references. Surprisingly, many of our other specimens contained the same anomaly. After discussion with my advisor, it was decided that the project would focus in on documenting these innervations in our specimens in order to establish a new pattern for anatomical literature. Indeed, this was the goal from the onset of the project: Identify and update discrepancies between representations and observations of the trigeminal nerve.
It was found that all 20 of our initial specimens contained the nerve pattern of interest. We have obtained 9 additional specimens for use in this and other projects, and dissections for each of the original 20 of these specimens have been completed. Four specimens have been undergone the complete MicroScribe process and one has been fully digitized using Maya.
This project has opened the door to many new studies surrounding the anatomy of the trigeminal nerve. In addition to continuing to move forward with the documentation of sublingual gland innervations, I have taken a particular interest in mapping the nerve branches connecting roots of molars to the inferior alveolar nerve. I am confident that the research I am currently conducting will continue to uncover new advances in the anatomical understanding of the trigeminal nerve.
Conclusion
My project has successfully showcased the need for data-driven models in the field of anatomy. Current technology makes it possible to rely less on artistic representations and more on digitally documented observations. The discovery of the undocumented nerve innervations found in the sublingual gland is just the beginning of corrections and updates that my research could make on current anatomical literature.
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