Variation in Lingual Nerve Course: A Human Cadaveric Study

Area of Science:

• Anatomy
• Oral Surgery
• Neuroscience

Background:

• The lingual nerve, a terminal branch of the mandibular nerve, exhibits significant anatomical variability.
• Its course and relationship with surrounding structures, including the mandibular alveolar crest and submandibular duct, are critical considerations in oral and maxillofacial surgery.

Purpose of the Study:

• To elucidate the precise anatomical course of the lingual nerve from the molar region to its tongue insertion.
• To provide morphometrical data on the lingual nerve's position relative to the alveolar ridge and mandibular border.
• To document the morphological variations of its terminal branches and its relationship with the submandibular duct.

Main Methods:

• Cadaveric dissection of 14 hemi-mandibles.
• Morphometrical analysis of the lingual nerve's distance to the alveolar ridge and mandibular border.
• Observation of the lingual nerve's course, looping patterns around the submandibular duct, and terminal branching in the tongue.

Main Results:

• The lingual nerve's mean distance to the alveolar ridge was 12.36 mm and to the mandibular border was 12.03 mm, with variations near molars (M1, M2, M3).
• The nerve coursed approximately 25.43 mm before deviating towards the tongue between the mesial of M1 and distal of M2.
• Thirteen nerves looped around the submandibular duct (average 6.92 mm), typically between M2 and M3, with most loops starting near M3.

Conclusions:

• Significant anatomical variations in the lingual nerve's course and its relationship with the submandibular duct and alveolar crest exist.
• Awareness of these lingual nerve variations is essential for minimizing nerve injury during surgical procedures in the oral cavity.
• These findings offer valuable insights for surgical planning involving the alveolar crest, submandibular gland/duct, and adjacent oral structures.