Lingual and Mylohyoid Nerves
The lingual and mylohyoid nerves are presented together due to their corresponding morphological features. These include a common origin from the posterior trunk of the mandibular nerve (third division of CN V), similar trajectories through the infratempo
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Lingual Nerve The lingual nerve arises from the posterior trunk of the mandibular nerve at a mean distance of 13.5–14.3 mm below the foramen ovale (Table 19.1) (Fig. 19.1). The lingual nerve is the largest branch of the mandibular nerve with a mean diameter ranging between 2.03 and 3.62 mm (Table 19.2). The lingual nerve courses lateral to the tensor veli palatini and medial to the lateral pterygoid muscle (Fig. 19.2). Approximately at the lower border of the lateral pterygoid muscle, the lingual nerve is joined by the chorda tympani at a mean distance of 8.4–11.4 mm inferior to the origin of the lingual nerve or at a mean distance of 15.1 mm below the foramen ovale, respectively (Table 19.1). The lingual nerve then crosses the medial pterygoid muscle on its anterolateral surface, passes below the mandibular attachment of the pterygomandibular raphe, and eventually approaches the lingual bone surface posterior to the third molar, in an area also described as the
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medial ridge of the retromolar triangle (Fig. 19.3). At the level of the posterior root of the third molar, the lingual nerve usually is covered only by the gingival mucoperiosteum. At the upper border of the mylohyoid line, the lingual nerve continues horizontally on the superior surface of the mylohyoid muscle and courses in close relation to the upper pole of the submandibular gland, giving off fibers to the submandibular ganglion. In the close vicinity of the upper surface of the posterior portion of the mylohyoid muscle, the submandibular duct crosses over the lingual nerve. After passing along the lingual bone plate of the mandibular body, the lingual nerve turns medially toward the tongue usually at the level of the first or second mandibular molar (Fig. 19.4) (Klepacek and Skulec 1994; Chan et al. 2010; Boffano et al. 2012; Benninger et al. 2013). The lingual nerve carries general sensory fibers as well as gustatory and secretomotor fibers via chorda tympani of CN VII to the tongue, floor of the mouth, and sublingual and submandibular glands
© Springer International Publishing Switzerland 2017 T. von Arx, S. Lozanoff, Clinical Oral Anatomy, DOI 10.1007/978-3-319-41993-0_19
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Lingual and Mylohyoid Nerves
Table 19.1 Anatomical distances (mm) related to lingual nerve (LN) Distance between LN and inferior alveolar nerve –
Junction of LN and chorda tympani *11.4
Author(s) Study material Vrionis et al. (1996) 6 adult cadaveric heads
N 12 sides
Bifurcation of LN from mandibular nerve –
Kim et al. (2004)
16 adult Korean cadaveric heads
32 sides
*14.3 (7.8–24.1)
**4.0 (0–7.7)
–
Erdogmus et al. (2008) Shinohara et al. (2010) Joo et al. (2013)
21 adult male cadaveric heads 15 adult Japanese cadaveric heads 10 adult cadaveric heads
42 sides
–
–
30 sides
*8.7 ± 4.2 (0–14)
–
*15.1 ± 5.8 (7.01–26.03) –
20 sides
*13.5 (6–32)
–
**8.4 (0–20)
MN
MA MA LN ChT
IAN IAA
LN
IAA IAN LN
MHN
Fig. 19.1 Right lingual nerve dissection following resection of the ramus and zygomatic arch in a cadaveric head. ChT chorda tympani, IA
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