Use of Digitally Annotated and Printed 3D Models for Teaching the Pterygopalatine Fossa
Authors: Ramirez Kristen Renee , Shearer Brian , Dorsainville Gregory , Harnik Victoria 
Published: April 2020

Anatomically deep and geometrically complex regions are difficult for students to visualize in gross dissections, overly simplified in models, and not faithfully depicted in 2D images. One such region is the pterygopalatine fossa which communicates with the infratemporal region, middle cranial fossa, cranial base, nasal and oral cavities, and face via 7 osteological foramina or fissures. Given the geometric complexity of this space, we aimed to create a 3D based educational tool for students to use in their pre‐clinical, dissection‐free head and neck anatomy course.

A cranium rendered from CT imaging was imported into Medium, a digital sculpting program, using the Oculus Virtual Reality (VR) system. The right half was removed, and the left half was divided into three sections via two parasagittal slices. The lateral parasagittal cut bisected the foramen rotundum and palatine canals, and the medial parasagittal cut bisected the left half of the nasal cavity. The only alterations to the morphology was an exaggeration of the palatine canal and the anterior and posterior openings of the Vidian canal to allow for the passage of wires during the lab exercise. The three sections of the cranium were then 3D printed. In addition to 3D printing, the model was annotated in Medium by drawing in the course of the maxillary artery and nerve and their branches, and the nerve of the Vidian canal in the pterygopalatine fossa and associated regions. The model showing the neurovasculature related to the pterygopalatine fossa was imported into Sketchfab, a 3D model publishing platform, where labels could be placed to identify structures and provide additional information. The labeled model was embedded into the digital lab manual for students to reference during the lab activity where they were directed to pass a wire through the various foramina and fissures in the region to understand the passage of the neurovasculature in and out of the pterygopalatine fossa.

The annotated digital model allowed students to visualize the completed course of these nerves and arteries while the printed model gave appreciation for the location, size, and orientation of the canals and foramina through which the pterygopalatine fossa communicates with other regions. This intervention was applied in the 2019 Living Anatomy: Head and Neck course, where students did not perform dissection but did have access to prosected cadavers and plastinations.

Student performance on the 2019 exam was statistically identical to the performance of previous cohorts in a traditional dissection‐based anatomy course (2018: 85.9%; 2019: 88.1%). The 2019 cohort on average scored lower on questions derived from the material from the lab that included this intervention compared to the 2018 cohort (2018: 84.82%; 2019: 80.76%). However, the pterygopalatine fossa question (97.09%) outperformed the nasal cavity (80.58%) and larynx/pharynx (78.5%) questions. Additionally, students ranked digitally annotated 3D models the 3rd highest activity or resource following faculty directed case studies and the prosected cadavers. Student exam results and feedback indicate a utility of providing physical objects with digital 3D reference material during anatomy instruction.