S12 Dissection Summary

S12 Dissection Summary

Part 1

    • Visualize the boundaries of the nasopharynx.
    • Identify structures of the nasopharynx, specifically pharyngeal tonsil, pharyngeal opening of pharyngotympanic (auditory) tube, torus tubarius, and salpingopharyngeal arch.

Part 2

    • Palpate the boundary between hard and soft palates.
    • Remove the mucosa inferior to the pharyngeal opening of the pharyngotympanic tube to expose the levator veli palatini m. and tensor veli palatini m. In this view, it will appear that the tensor veli palatini m. is under (anatomically, it is lateral to) the levator veli palatini m.
    • With blunt dissection, locate the ascending palatine a. posterior to the levator veli palatini m.
    • Locate the palatoglossal and palatopharyngeal arches. The tongue will need to be moved inferomedially.
    • Between the palatoglossal and palatopharyngeal arches, locate the tonsillar fossa (bed). Locate the palatine tonsil, if present.
    • Remove the mucosa of the palatoglossal and palatopharyngeal arches to uncover the palatoglossus and palatopharyngeus mm. Remove the mucosa on the uvula of the soft palate to uncover the fibers of the musculus uvulae m. Locate the palatine aponeurosis.
    • Pull the root of the tongue anteriorly, and using blunt dissection, locate the glossopharyngeal n. (CN IX) inferior to the tonsillar fossa (bed).

Part 3

    • Carefully pull the mucosa from the hard palate using forceps. Locate the neurovasculature in this area: greater palatine a. and n., lesser palatine a. and n., and nasopalatine n.

Part 4

    • On one side only, follow the greater palatine n. and a. superiorly from the greater palatine foramen. Carefully remove any remaining mucosa and muscles posterior to the nasal conchae, and open the medial wall of the greater palatine canal (i.e. remove the bone of the lateral wall of the nasopharynx posterior to the conchae and anterior to the opening of the pharyngotympanic tube). Locate neurovasculature associated with this area: greater palatine n., lesser palatine n., descending palatine a., greater palatine a., and lesser palatine a. Relocate previously dissected nerves associated with the conchae and nasal meatuses: posterior superior lateral nasal brs. and posterior inferior nasal nn.
    • Continue to remove connective tissue superiorly until the sphenoidal sinus is reached. Locate the pterygopalatine ganglion. Locate the nerve of pterygoid canal and associated artery of pterygoid canal. The n. of the pterygoid canal posteriorly joins the pterygopalatine ganglion.

Part 5

    • On one side only, relocate the mandibular n. (V3) in the infratemporal fossa. Continue medially and superiorly to enter the pterygopalatine fossa through the lateral side. Locate structures in this area: maxillary a. (3rd part) and branches (posterior superior alveolar a., infra-orbital a., sphenopalatine a., and descending palatine a.
    • ) and maxillary n. and its branches.

Part 6

    • On the ipsilateral side of the donor that the eyeball was enucleated, reflect the inferior oblique m. from its attachment to the orbital part of the maxilla. Be careful to preserve the infra-orbital neurovasculature deep to the muscle. Locate the infra-orbital n. and a. in the infra-orbital groove. Portions of the maxilla may need to be removed (chipped away) in order to follow the nerve posteriorly.
    • As the maxilla is removed, locate the superior alveolar brs. and aa. These are very small and not easy to dissect. You may choose to transilluminate the maxillary sinus in order to visualize the neurovasculature of this area.