Year : 2010 | Volume
: 21 | Issue : 1 | Page : 141--142
An unusual communication between the mylohyoid and lingual nerves in man: Its significance in lingual nerve injury
Bhagath Kumar Potu, Suhani Sumalatha D'Silva, P Thejodhar, Nishita C Jattanna
Department of Anatomy, Kasturba Medical College, Manipal University, Karnataka - 576 104, India
Bhagath Kumar Potu
Department of Anatomy, Kasturba Medical College, Manipal University, Karnataka - 576 104
The mylohyoid nerve is the branch of the inferior alveolar nerve (IAN) which arises above the mandibular foramen. An abnormal communication between the mylohyoid nerve and lingual nerve (LN) was noted during the routine dissection of a male cadaver. Communicating branches between IAN and LN have been identified as a possible explanation for the inefficiency of mandibular anesthesia. The communication between mylohyoid and lingual nerve was found in this case after the LN passes in close relation to third molar tooth, which makes it more susceptible to injury during third molar extractions.
|How to cite this article:|
Potu BK, D'Silva SS, Thejodhar P, Jattanna NC. An unusual communication between the mylohyoid and lingual nerves in man: Its significance in lingual nerve injury.Indian J Dent Res 2010;21:141-142
|How to cite this URL:|
Potu BK, D'Silva SS, Thejodhar P, Jattanna NC. An unusual communication between the mylohyoid and lingual nerves in man: Its significance in lingual nerve injury. Indian J Dent Res [serial online] 2010 [cited 2013 Dec 6 ];21:141-142
Available from: http://www.ijdr.in/text.asp?2010/21/1/141/62792
The mylohyoid nerve (MHN) is a branch of the inferior alveolar nerve (IAN), which arises above the mandibular foramen. The nerve then passes downward and anteriorly within the mylohyoid groove on the medial surface of the mandible. The nerve courses anteriorly and parallel to the mylohyoid muscle and giving branches that provide motor innervation to the mylohyoid and anterior belly of the digastric muscles.  The mylohyoid muscle plays an important role in chewing, swallowing, respiration, and phonation.  It has been analyzed that the MHN might have a role in the sensory innervation of the chin.  The role of the MHN in the mandibular posterior tooth sensation is still a controversial issue.  During routine dissection in the Department of Anatomy, Kasturba Medical College, Manipal University, an abnormal communication between the mylohyoid and lingual nerves of a middle aged male cadaver was noted. This variation was found only in 1 of 15 cadavers studied. In the present case, immediately after the Inferior alveolar nerve (IAN) entered the inferior alveolar canal, the MHN appeared thicker than usual. Approximately at the level of the intermediate tendon of the digastric muscle, the MHN gave of a thick branch that joined the lingual nerve (LN). Thereafter, the MHN followed its normal course and branching pattern [Figure 1]. No other anatomical variations were found in the origin of inferior alveolar or the lingual nerves. Also, no communicating branches between these two nerves were found. The LN, after receiving this communicating branch from the MHN, was observed taking its normal course and branching pattern. Communicating branches between the IAN and the LN were well described in literature  and these communications have been identified as a possible explanation for the inefficiency of mandibular anesthesia.  The presence of communicating branches between the inferior alveolar and lingual nerves is very commonly mentioned in most of the anatomical text books. Nevertheless, a communicating branch between the mylohyoid and lingual nerves is seldom described in literature and also not regularly mentioned in the anatomical textbooks.
The communication between the mylohyoid and lingual nerves in this case was found to occur after the LN passes in close relation to the third molar tooth. Since this close relationship of the LN and the third molar tooth makes it susceptible to injury during the third molar extraction,  the presence of a nerve communication like the one described in this case would help in the LN function recovery.  The communicating branch between the MHN and LN might also innervate the tongue and surgeons should be aware of this variation to avoid unexpected findings after oral nerve surgeries.
Authors would like to thank Dr. Narga Nair, Professor and Head of the Department of Anatomy for her support.
|1||Clark S, Reader A, Beck M, Meyers WJ. Anesthetic efficacy of the mylohyoid nerve block and combination inferior alveolar nerve block/mylohyoid nerve block. Oral Surg Oral Med Oral Pathol Oral Radiol Endo 1999;87:557-63.|
|2||Ren M, Mu L. Intrinsic properties of the adult human mylohyoid muscle: Neural organization, Fiber-type distribution, and myosin heavy chain Expression. Dysphagia 2005;20:182-94.|
|3||Guyot L, Layoun W, Richard O, Cheynet F, Gola R. Alteration of chin sensibility due to damage of the cutaneous branch of the mylohyoid nerve during genioplasty. J Oral Maxillofac Surg 2002;60:1371-3.|
|4||Sakamoto Y, Akita K. Spatial relationships between masticatory muscles and their innervating nerves in man with special reference to the medial pterygoid muscle and its accessory muscle bundle. Surg Radiol Anat 2004;26:122-7.|
|5||Racz VL, Maros T, Seres-Sturm L. Anatomical variations of the nervus alveolaris inferior and their importance for the practice. Anat Anz 1981;149:239-332.|
|6||Behnia H, Kheradvar A, Shahrokhi M. An anatomic study of the lingual nerve in the third molar region. J Oral Maxillofac Surg 2000;58:649-51.|
|7||Fazan VP, Rodrigues Filho OA, Matamala F. Communication between the mylohyoid and lingual nerves: Clinical implications. Int J Morphol 2007;25:561-4.|