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Aberrant buccal nerve encountered at third molar surgery
Aberrant buccal nerve encountered at third molar surgery S. Singh, B.D.S. (Ed.), Edinburgh, DEPARTMENT
Scotland
OF ORAL SURGERY, UNIVERSITY
OF EDINBURGH
The retromolar region is routinely explored by oral surgeons, and it is surprising that anatomic in this area are not more commonly found. The short case presented here involved a variation buccal nerve which previously had been encountered only in anatomic dissection.
F
or the surgical removal of a mesioangularly impacted lower third molar, a mucoperiosteal flap was raised to expose the alveolar bone overlying the roots of the tooth, the retromolar fossa, and the lower part of the anterior border of the ramus. Following reflection of the flap, a slender nerve was observed emerging from a small foramen in the retromolar fossa, level with the distal aspect of the third molar and about 5 mm. from the superior border of the mandible. The nerve ran laterally from the foramen for about 20 mm. before passing under the reflected flap in an anteroinferior direction. The nerve was subsequently damaged and a small section was removed for histologic examination, which confirmed it to be a nerve, 0.5 mm. in diameter, with predominantly myelinated fibers only. Postoperative follow-up showed the patient to have paresthesia of the buccal sulcus and gingivae from the retromolar to the canine region, although vitality tests of all the mandibular teeth showed bilaterally equal responses. Unilateral paresthesia of the buccal sulcus subsequent to trauma to the nerve, would suggest it to be a variation of the buccal nerve as described by Turner.’ This variation (Turner’s) arose from the inferior alveolar nerve in its bony canal, emerged from a small foramen in the alveolar border of the
142
variations of the
mandible close to the ramus, and replaced the usual terminal branch of the anterior trunk of the mandibular nerve. More recently Carter and Keen2 have described neurovascular bundles leaving foramina in the retromolar region which were traced to the temporalis. These bundles were found to be in communication with an intrabony, neurovascular network lateral to the molar teeth and occasionally had a direct connection with branches entering the roots of the molar teeth. The direction of the nerve reported in this case, together with the responses to vitality testing postoperatively, would seem to rule out this further variation of the branches of the mandibular nerve and, further, suggest that the variation in this case is similar to that described by Turner. REFERENCES
1. Turner, W.: On Some Variations in the Arrangement of the Nerves of the Human Body, Nat. Hist. Rev. 4: 612-617, 1864. 2. Carter, R. B., and Keen, E. N.: The Intra-mandibular Course of the Inferior Alveolar Nerve, J. Anat. 10s: 433-440, 1971. Reprint
requests
to:
Dr. S. Singh Department of Oral Surgery University of Edinburgh Edinburgh, Scotland
0030-4220/81/080142
+ Ol$OO.lO/O~
1981 The C. V. Mosby
Co.
Scotland
OF ORAL SURGERY, UNIVERSITY
OF EDINBURGH
The retromolar region is routinely explored by oral surgeons, and it is surprising that anatomic in this area are not more commonly found. The short case presented here involved a variation buccal nerve which previously had been encountered only in anatomic dissection.
F
or the surgical removal of a mesioangularly impacted lower third molar, a mucoperiosteal flap was raised to expose the alveolar bone overlying the roots of the tooth, the retromolar fossa, and the lower part of the anterior border of the ramus. Following reflection of the flap, a slender nerve was observed emerging from a small foramen in the retromolar fossa, level with the distal aspect of the third molar and about 5 mm. from the superior border of the mandible. The nerve ran laterally from the foramen for about 20 mm. before passing under the reflected flap in an anteroinferior direction. The nerve was subsequently damaged and a small section was removed for histologic examination, which confirmed it to be a nerve, 0.5 mm. in diameter, with predominantly myelinated fibers only. Postoperative follow-up showed the patient to have paresthesia of the buccal sulcus and gingivae from the retromolar to the canine region, although vitality tests of all the mandibular teeth showed bilaterally equal responses. Unilateral paresthesia of the buccal sulcus subsequent to trauma to the nerve, would suggest it to be a variation of the buccal nerve as described by Turner.’ This variation (Turner’s) arose from the inferior alveolar nerve in its bony canal, emerged from a small foramen in the alveolar border of the
142
variations of the
mandible close to the ramus, and replaced the usual terminal branch of the anterior trunk of the mandibular nerve. More recently Carter and Keen2 have described neurovascular bundles leaving foramina in the retromolar region which were traced to the temporalis. These bundles were found to be in communication with an intrabony, neurovascular network lateral to the molar teeth and occasionally had a direct connection with branches entering the roots of the molar teeth. The direction of the nerve reported in this case, together with the responses to vitality testing postoperatively, would seem to rule out this further variation of the branches of the mandibular nerve and, further, suggest that the variation in this case is similar to that described by Turner. REFERENCES
1. Turner, W.: On Some Variations in the Arrangement of the Nerves of the Human Body, Nat. Hist. Rev. 4: 612-617, 1864. 2. Carter, R. B., and Keen, E. N.: The Intra-mandibular Course of the Inferior Alveolar Nerve, J. Anat. 10s: 433-440, 1971. Reprint
requests
to:
Dr. S. Singh Department of Oral Surgery University of Edinburgh Edinburgh, Scotland
0030-4220/81/080142
+ Ol$OO.lO/O~
1981 The C. V. Mosby
Co.