Functional anatomy of the mandibular nerve: Consequences of nerve injury and entrapment

Abstract

Various anatomic structures including bone, muscle, or fibrous bands may entrap and potentially compress branches of the mandibular nerve (MN). The infratemporal fossa is a common location for MN compression and one of the most difficult regions of the skull to access surgically. Other potential sites for entrapment of the MN and its branches include, a totally or partially ossified pterygospinous or pterygoalar ligament, a large lamina of the lateral plate of the pterygoid process, the medial fibers of the lower belly of the lateral pterygoid muscle and the inner fibers of the medial pterygoid muscle. The clinical consequences of MN entrapment are dependent upon which branches are compressed. Compression of the MN motor branches can lead to paresis or weakness in the innervated muscles, whereas compression of the sensory branches can provoke neuralgia or paresthesia. Compression of one of the major branches of the MN, the lingual nerve (LN), is associated with numbness, hypoesthesia, or even anesthesia of the tongue, loss of taste in the anterior two thirds of the tongue, anesthesia of the lingual gums, pain, and speech articulation disorders. The aim of this article is to review, the anatomy of the MN and its major branches with relation to their vulnerability to entrapment. Because the LN expresses an increased vulnerability to entrapment neuropathies as a result of its anatomical location, frequent variations, as well as from irregular osseous, fibrous, or muscular irregularities in the region of the infratemporal fossa, particular emphasis is placed on the LN.

Oral Territorial Neurovascular Considerations in Implant Surgery

“…This can occur where the nerve passes through a fibro-osseous canal or foramen like mental foramen and is relatively fixed, from impingement by an anatomic structure, or from entrapment of the nerve between the soft and hard tissues. Thus, it is important to know the anatomy of inferior alveolar nerve and its major branches with relation to their vulnerability to entrapment (Piagkou et al, 2011) The IAN normally descends medial to the lateral pterygoid muscle passes between the sphenomandibular ligament and the mandibular ramus, and then enters the mandibular canal through the mandibular foramen. In the mandibular canal it runs downward and forward, generally below the apices of the teeth until below the first and second premolars, where it divides into the terminal incisive and mental branches (Khan et al, 2010;KrmpoticNemanic et al, 2001).…”

“…As such, a medially displaced disccould interfere mechanically with this nerve. This could explain the www.intechopen.com sharp, shooting pain felt locally in the joint with jaw movements as well as the pain and other sensations projecting to the terminal area of distribution of the nerve branches near thetemporomandibular joint, such as the ear, temple, cheek, tongue, and teeth (Piagkou et al, 2011;Johansson et al, 1990). The MN exits the mandible through the mental foramen, divides into three branches deep to the depressor anguli, oris muscle, and supplies the skin and mucous membrane of the lower lip, the skin of the chin, and the vestibular gingiva of the mandibular incisor (Standring et al, 2005;Moore, 1983;April, 1990;Woodburne & Burkel 1994).…”

Morphology and Location of Surface Landmarks of Foramen Ovale in Kenyans

“…This has been to find out which side is affected more and perhaps correlate that with anatomical data, on the size of foramen ovale and on ligaments civinini and hyrtle, gleaned from cadaveric studies (Piagkou et al, 2011). However in our study the differences in size and morphology between the left and right sides are not statistically significant pointing to a multifactorial cause of trigeminal neuralgia (Bowsher, 1997).…”

Clinical Reasoning: A case of unilateral facial pain

“…Additionally, selective motor involvement of the mandibular nerve has been described. 5,6 Third, it is useful to consider the contralateral consequences of unilateral loss of a paired cranial nerve. Finally, cranial neuropathies or asymmetry of cranial nerve function should raise suspicion for a lesion involving the foramina through which the cranial nerves exit the skull.…”