Mandibular nerve entrapment in the infratemporal fossa.

The posterior trunk of the mandibular nerve (V(3)) comprises of three main branches. Various anatomic structures may entrap and potentially compress the mandibular nerve branches. A usual position of mandibular nerve (MN) compression is the infratemporal fossa (ITF) which is one of the most difficult regions of the skull base to access surgically. The anatomical positions of compression are: the incomplete or complete ossified pterygospinous (LPs) or pterygoalar (LPa) ligament, the large lamina of the lateral plate of the pterygoid process and the medial fibres of the lower belly of the lateral pterygoid (LPt). A contraction of the LPt, due to the connection between nerve and anatomic structures (soft and hard tissues), might lead to MN compression. Any variations of the course of the MN branches can be of practical significance to surgeons and neurologists who are dealing with this region, because of possibly significant complications. The entrapment of the MN motor branches can lead to paresis or weakness in the innervated muscle. Compression of the sensory branches can provoke neuralgia or paraesthesia. Lingual nerve (LN) compression causes numbness, hypoesthesia or even anaesthesia of the mucous of the tongue, anaesthesia and loss of taste in the anterior two-thirds of the tongue, anaesthesia of the lingual gums, as well as pain related to speech articulation disorders. Dentists should be very suspicious of possible signs of neurovascular compression in the region of the ITF.