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Asia Pacific Journal of Research
Vol: I. Issue XXV, March 2015
ISSN: 2320-5504, E-ISSN-2347-4793
AN ANOMALOUS COMMUNICATION BETWEEN NERVE TO MYLOHYOID AND THE LINGUAL
NERVES AND ITS CLINICAL IMPLICATIONS – ACASE REPORT
1
Huban Thomas R*, 2Prasanna LC, 3Kumar M R Bhat,4Prakash Babu B
1
Senior Grade Lecturer and Corresponding Author, 2Associate Professor,
3
Additional Professor, 4Associate Professor,
Department of Anatomy, Kasturba Medical College, Manipal University, Manipal, India
ABSTRACT
The mandibular nerve is the largest of the three branches of the trigeminal nerve. The inferior alveolar
nerve also called as inferior dental nerve is a branch of the posterior division of the mandibular nerve.Before
traversing the mandibular foramen, it first gives off the nerve to the mylohyoid, a motor nerve supplying
the mylohyoid and the anterior belly of the digastric muscles.The lingual nerve is a branch of the posterior
division mandibular nerve, which receives sensory innervations from the oral part of the tongue. During routine
dissection in the Department of Anatomy, we found the presence of an anomalouscommunication between the
nerve to mylohyoid and lingual nerves on the hyoglossus muscle in anadult maleformalin fixed
cadaver.Variations in the course of nerve to mylohyoid and its communication with the lingual nerve, have not
been satisfactorily described in the anatomical or surgical literature.Variant branching pattern of the
mandibular nerve are of great clinical importance since these variations can cause failure to obtain adequate
local anesthesia in oral and dental procedures. We assume that this anomalous communication may contain
sensory fibers from the inferior alveolar nerve entering in to the lingual nerve through nerve to mylohyoid or
some fibres of the motor root ofthe trigeminal nervepassing through the lingual nerve to reach the nerve to
mylohyoid.
Keywords: mylohyoid nerve, lingual nerve, anomalous communication.
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Asia Pacific Journal of Research
Vol: I. Issue XXV, March 2015
ISSN: 2320-5504, E-ISSN-2347-4793
Introduction
The mandibular nerve is the largest of the three branches or divisions of the trigeminal nerve. It is made up of a
large sensory root proceeding from the inferior angle of the trigeminal ganglion, a small motor root which
passes beneath the ganglion, and unites with the sensory root, just after its exit through the foramen ovale. The
main trunk of the mandibular nerve lies in the infratemporal fossa where it divides in to a small anterior division
and large posterior division.
Inferior alveolar nerveis the larger terminal branch of the posterior division of the mandibular nerve. It runs
vertically downwards lateral to the medial pterygoid and to the sphenomandibular ligament and enters the
mandibular foramen. Before entering the mandibular foramen, it first gives off the nerve to the mylohyoid, a
motor nerve supplying the mylohyoid and the anterior belly of the digastric muscles.
Lingual nerve is one of the two terminal branches of the posterior division of the mandibular nerve. This nerve
is sensory to the anterior two-thirds of the tongue and to the floor of the mouth. The fibres of the chorda
tympani carry secretomotor to the submandibular and sublingual salivary glands and gustatory to the anterior
two-thirds of the tongue, are also passes through the lingual nerve.
Case Presentation
During routine dissection in the Department of Anatomy, we found the presence of an anomalous
communication between the nerve to mylohyoid and lingual nerves on the hyoglossus muscle in an adult
male formalin fixed cadaver.This communication is unilateral and absorbed only on left side. Formation,
course, relations and branching pattern of the mandibular nerve were as usual except above said
anomalous
communication.
Figure 1– Photograph showing the abnormal communication between the lingual and
mylohyoidnerves. LN – Lingual nerve;
MHN –Mylohyoid nerve.
Asterisks showing the communication between the two nerves.
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Asia Pacific Journal of Research
Vol: I. Issue XXV, March 2015
ISSN: 2320-5504, E-ISSN-2347-4793
Discussion
Presence of communicating nerves between branches of the posterior division of mandibular nerve is thought to
serve as an alternative route for maintaining the functional integrity of the structures innervated by it. 1The
presence of communicating branches between the inferior alveolar and lingual nerves is frequently reported in
the literature.2 This kind of communication is thought to be responsible for inadequate mandibular
anaesthesia.3However, a communicating branch between the mylohyoid and lingual nerves is seldom described
in literature.4 It has been reported that the mylohyoid nerve might have a role in the sensory innervation of the
chin and the lower incisor teeth. Some of the sensory components of the mylohyoid nerves, instead of
innervating the teeth or chin, might also innervate the tongue.4 variations on the branching pattern of the
mandibular nerve frequently account for the failure to obtain adequate local anesthesia in routine oral and dental
procedures.5
Conclusion
Variant branching pattern of the mandibular nerve are of great clinical importance since these variations can
cause failure to obtain adequate local anesthesia in oral and dental procedures. Surgeons might be aware of this
variation for the correct interpretation of the unexpected findings after oral nerves injury.
References:
1. Thotakura, B.,Rajendran, S S.,Gnanasundaram, V.,Subramaniam, A.,(2013) ‘Variations in the posterior
division branches of the mandibular nerve in human cadavers’,Singapore Med J, Vol 54(3), pp 149-151.
2. Rácz, L., Maros., T(1981) ‘The anatomic variants of the lingual nerve in human’,AnatAnz, Vol
149,pp64-71.
3. Anil, A., Peker, T., Turgut,HB.,Gülekon, IN., Liman, F.,(2003) ‘Variations in the anatomy of the
inferior alveolar nerve’. Br J Oral MaxillofacSurg, Vol 41,pp236-239.
4. Fazan,VPS., Rodrigues, FOA., Matamala, F,. (2007) ‘Communication between the mylohyoid and
lingual nerves: clinical implications’,Int J Morphol, Vol 25, pp561-564.
5. Jablonski, N.G., Cheng, C. M., Cheng, L. C. & Cheung, H. M. (1985) ‘Unusual origins of the buccal and
mylohyoid nerves’. Oral Surg. Oral Med. Oral Pathol.,Vol 60, pp487-488.
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