Variations of the lingual and inferior alveolar nerves and their anomalous relationship with the maxillary artery

The infratemporal fossa is a compact space with multiple contents. Explicit anatomical knowledge regarding the relationship between these neurovascular structures becomes imperative during any surgical intervention. Literature is abounding with variations in this region. It encompasses communication between branches of the mandibular nerve or entrapment of nerves by bony bridges, or even abnormal course and branching pattern of the arteries. However, there are many other variabilities in these structures that are less reported or unreported. The present study is an effort to report the characteristic variations of the lingual and inferior alveolar nerves and their anomalous relationship with the maxillary artery in the infratemporal fossa. The study was conducted bilaterally on 26 adult cadavers. The variations in the origin and course of the lingual & inferior alveolar nerves were noted. The course of the maxillary artery and its relation to the lingual and inferior alveolar nerves was also recorded. The variations were explained under the following types: a) communication between the lingual and inferior alveolar nerves, b) existence of a pterygospinous ligament/bar overlying/separating the lingual and inferior alveolar nerves, c) abnormal course/ absence of the chorda tympani nerve and an alternate taste pathway, d) multiple roots of the lingual and inferior alveolar nerves and e) the unusual course of the maxillary artery. Knowledge of these variations would aid the head & neck surgeons in minimizing the compression symptoms and also avoiding postoperative complications

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Accessory mental foramina and nerves: Application to periodontal, periapical, and implant surgery.

Recent studies investigating accessory mental foramina using developments in diagnostic imaging have primarily defined the morphology of the foramina; however, few studies have described the structures passing through them. Additional clinical knowledge of the foramina is therefore required for preoperative diagnosis prior to surgery, including implant, periodontal and periapical surgery. In this study, we investigated the accessory mental foramina and the associated nerves and arteries in donated cadaveric mandibles using anatomical and radiological observation methods. We examined 63 mandibles with overlying soft tissue by cone-beam computed tomography and noted the existence of the accessory mental foramina. Mandibles with accessory mental foramina were subsequently analyzed. Additionally, the neurovascular bundles passing through these foramina were dissected using anatomical methods.The incidence of accessory mental foramina was 14.3%. The larger foramina tended to be located anteriorly or superiorly and proximal to the mental foramen, while the smaller foramina tended to be located posterosuperiorly and distal to the mental foramen. The mental foramen ipsilateral to the accessory mental foramen was smaller than the one contralateral to it. The comparatively distant and large accessory mental foramen included an artery.This study elucidated the relationship between accessory mental foramina and the associated nerves and arteries. We believe that the results will contribute to the clinical dentistry field.

Revisión bibliográfica de la anatomía del nervio dentario inferior y su implicancia en la cirugía implantológica de los sectores posteriores mandibulares / A review of the literature on inferior alveolar nerve anatomy and its involvement with implant surgery of the posterior mandibular sectors

El nervio dentario inferior es una de las estructuras anatómicas más importantes a considerar previo a la colocación de implantes dentales en la mandíbula. La lesión de este nervio es una situación temida por los pacientes y los profesionales por la posibilidad de daño permanente en su conducción nerviosa. Es fundamental para todos los odontólogos que realicen maniobras quirúrgicas próximas a la entidad nerviosa, conocer ampliamente su recorrido, distribución y características normales, para prevenir la injuria del mismo y sus indeseables consecuencias. El objetivo de esta publicación es brindar información actualizada del conocimiento del nervio dentario inferior y su relación con la implantología oral...

Severe adverse reactions to dental local anaesthetics: prolonged mandibular and lingual nerve anaesthesia.

BACKGROUND: Prolonged anaesthesia may occur following dental local anaesthetic blocks. This paper reviews the possible mechanisms of injury. Direct injury to the nerve by the needle, although commonly thought to be the mechanism, is unlikely. It is much more likely that the injury is from neurotoxicity and/or interference with the vascularization of the nerve. METHODS: Estimation of the frequency of injury was complicated by the fact that although local anaesthetics are prescription-only (S4) drugs, they are supplied without prescription by dental supply houses. Unlike all other S4 drugs, there is no statutory requirement to record supply. The pharmaceutical and supply houses relied on that and 'commercial confidentiality' to not supply information. RESULTS: An informed estimate of 1 in 27 415 was made but this figure has wide confidence limits. Management of cases of prolonged anaesthesia following local anaesthetic injection is discussed. CONCLUSIONS: Patients who suffer this uncommon complication suffer considerable distress and feel injured, so care must be exhibited in their management. Specialist referral is recommended.

Comparison of microsuture, interpositional nerve graft, and laser solder weld repair of the rat inferior alveolar nerve.

PURPOSE: Intraosseous repair of nerves involves difficulty of access and there is concern that bone healing may interfere with repair outcomes. The present report describes the effect of 3 separate repair techniques on recovery from section of the rat intraosseous inferior alveolar nerve, with reference to the mental nerve distal and the trigeminal ganglion proximal to the nerve section. MATERIALS AND METHODS: Unilateral exposure of the inferior alveolar nerves of 28 rats was achieved through bone windows. Nerves were sectioned and rats were assigned to 1 of 4 groups (n = 7): untreated controls, microsuture repair, interpositional nerve grafts from the femoral nerve, or laser solder weld repair. Animals were sacrificed 1 year after surgery for histologic evaluation of the mental nerve, inferior alveolar nerve, and trigeminal ganglion compared with unoperated contralateral nerves. RESULTS: Compared with the unoperated contralateral nerves, nerve section substantially decreased mental nerve fiber number, mental nerve myelination, mental nerve fiber diameter, inferior alveolar nerve vascularity, trigeminal neuron number, and trigeminal neuron horseradish peroxidase tracer uptake and increased trigeminal ganglion degenerate neurons (P < .001). All 3 forms of repair substantially decreased these effects (P < .05). Interpositional nerve graft was least effective (P < .05). Nonetheless, mental nerve fiber diameter was significantly decreased compared with unsectioned nerves after microsuture and laser solder weld repair (P < .05). CONCLUSIONS: Intraosseous repair of the inferior alveolar nerve decreases peripheral and central signs of degeneration. Clinical hyperesthesia after repair may reflect a predominance of small fibers after recovery.

An unusual relationship between the inferior alveolar nerve, lingual nerve and maxillary artery / Una inusual relación entre los nervios alveolar inferior y lingual y la arteria maxilar

The knowledge of the neurovascular relationships of the infratemporal region is relevant in odontostomatology practice. In this article we present a case of atypical communication between the inferior alveolar nerve and lingual nerve associated with a change in relations with the maxillary artery, and discusses some clinical implications that these relations have on the development of the suplementary innervation and the anesthesia.

El conocimiento de las relaciones entre los elementos neurovasculares de la región infratemporal es relevante en la práctica odontoestomatológica. En el presente artículo presentamos el caso de una comunicación atípica entre el nervio alveolar inferior y el nervio lingual asociados a una variación en las relaciones con la arteria maxilar, y sediscut en algunas implicancias clínicas que estas relaciones tienen en el desarrollo de inervación suplementaria y en la práctica anestésica.

Labiomandibular paresthesia caused by endodontic treatment: an anatomic and clinical study.

Labiomandibular paresthesia after root canal treatment is an accident that is still too frequent despite the development of new endodontic techniques. The aim of this anatomical and clinical study is to advance the understanding of how accidents occur so as to avoid them. This anatomical study made it possible to determine the variability of proximity of the apex of the tooth root to the mandibular bundle, as well as the relationship between the nerve and its satellite artery, and to understand how endodontic filling material spreads into the cancellous bone. The clinical study, which included examination with conventional radiology as well as with imaging techniques, enabled us to identify the exact location of the filling material in relation to the mandibular bundle and to correlate this to the occurrence of clinical symptoms and their diverse manifestations.

Trigeminal neuralgia secondary to Chiari's malformation--treatment with ventriculoperitoneal shunt.

BACKGROUND: Trigeminal neuralgia (TN) is most commonly related to vascular compression of the trigeminal nerve. Trigeminal neuralgia associated with Chiari's malformation and associated hydrocephalus are rare. CASE DESCRIPTION: A 31-year-old male presented with classical TN affecting the mandibular division of the right trigeminal nerve. His symptoms were poorly controlled with increasing doses of carbamazepine. Magnetic resonance imaging scan of brain revealed Chiari's type I malformation and associated hydrocephalus. Approximately 1 month after insertion of a programmable ventriculoperitoneal shunt, his TN resolved. CONCLUSIONS: Chiari's malformation and hydrocephalus are rare associates of TN. The pathophysiology of TN in these cases may be due to neurovascular conflict, related to raised intracranial pressure from the hydrocephalus and/or the small posterior fossa volume in these patients. Drainage of associated hydrocephalus may be an effective surgical treatment.

Anatomía quirúrgica del nervio auriculotemporal en el acceso pre-auricular / Surgical anatomy of the auriculotemporal nerve in the pre-auricular acces

Con el objetivo de aportar datos anatómicos, que posibiliten el acceso a la región pre-auricular, con menor riesgo de lesión del nervio auriculotemporal en procedimientos quirúrgicos, fue realizada esta investigación, sobre las relaciones topográficas y biométricas de este nervio con la arteria y vena temporales superficiales y el trago. Fueron disecadas 24 hemicaras de cadáveres fijados con formaldehído al 10 por ciento, disponibles en el Laboratorio de Anatomía del Departamento de Morfología Humana de la Universidad Federal de Alagoas, Brasil. En siete casos (29,2 por ciento) el nervio subía posteriormente a los vasos temporales superficiales, y en otros siete (29,2 por ciento), subía junto a la vena. En tres casos (12,5 por ciento) el nervio emergía junto con la arteria. En dos casos (8,3 por ciento), el nervio estaba en posición intermedia. En cinco casos (20,8 por ciento), el nervio subía junto con ambos vasos. La menor distancia del nervio auriculotemporal a la línea pre-auricular fue de 0,3 mm, y la mayor fue de 11,5 mm, con media de 1,89 mm. La menor distancia del nervio con la arteria temporal superficial fue de 0,1 mm, y la mayor fue de 14,6 mm, con media de 8,66 mm, situándose la arteria anterior. Cuando la vena era anterior al nervio, la menor distancia entre sí, fue de 0,2 mm y la mayor, 10,9 mm, con media de 2,91 mm. Cuando la vena estaba en posición posterior, la distancia mínima fue de 0,1 mm, y la máxima de 9,4 mm, siendo la media de 2,54 mm. Concluimos que el nervio auriculotemporal presenta posición variable en la región pre-auricular y es la estructura más próxima a la línea pre-auricular.

Innervation of human trigeminal nerve blood vessels.

Film preparations and histological sections of human trigeminal nerve impregnated with silver nitrate and treated according to Falck-Hillarp revealed a rich innervation within the intraneural blood vessels. Highly diverse and complex neural interconnections were noted in the arterioles and venules of the trigeminal ganglion capsule as well as in the epineurium and external layers of the perineurium of the trigeminal nerve branches. Neural plexuses were detected on the vessel walls within these layers. Sensory innervation of the neural blood vessels was mainly relegated to polyvalent tissue-vascular receptors with adrenergic neural plexuses encountered on the walls of the intraneural vessels.

[Valentin's nerve, its role in the innervation of the chin region. Preliminary report]. / Le nerf de Valentin, son rôle dans l'innervation de la région mentonnière. Rapport préliminaire.

The mylo-hyoid nerve, a branch of the inferior alveolar nerve, gives rise to many motor and sensory branches. Motor branches innervate the anterior belly of the digastric muscle. Sensitive branches innervate the submandibular gland and also the skin just under the bony chin. Valentin's nerve, the terminal cutaneous branch of the myo-hyoid nerve (described by Valentin in 1843), can be damaged by horizontal mentoplasty (sliding-mentoplasty). Sensory disorders (hypoesthesia, anesthesia) can occur in case of Valentin's nerve injury without lesions to the mental nerve.

Oral complications associated with sickle cell anemia: a review and case report.

Sickle cell anemia is a multisystem disease that can affect the oral region. This article reviews previously reported oral complications associated with this disease and describes the cause of these problems. A case history describes a patient with multiple oral problems after a sickle cell crisis. The diagnostic and management problems of this case are highlighted. The need for a multidisciplinary approach to the care of these patients is emphasized.

Sickle cell disease: a diagnostic dilemma.

The case history is described of a patient with sickle cell anaemia who developed a unilateral infarct of the mandible following a sickle cell crisis. The interruption of the blood supply resulted in an anaesthesia of the inferior dental nerve and pulpal necrosis of otherwise sound premolar and molar teeth. The diagnostic and management difficulties of the case are discussed, and recommendations are made for treatment of such patients in light of the problems encountered.

Haemodynamic and immunohistochemical studies of rat incisor pulp after denervation and subsequent re-innervation.

The effects of injury to the inferior alveolar nerve on the distribution of neuropeptides and neurogenic blood-flow reactions were studied in rat mandibular dental pulp. In normal incisor pulps, calcitonin gene-related peptide (CGRP)-like immunoreactivity was common, while substance P- and neurokinin (NKA)-positive nerve fibres were much less abundant. There were no signs of vasoactive intestinal peptide-like, neuropeptide Y-like or 5-hydroxytryptamine-like immunoreactivity. In normal pulps, electrical stimulation (100 microA, 5 ms, 15 Hz for 30 s) of the tooth crown resulted in transient vasoconstriction followed by vasodilation, which was enhanced after alpha-adrenoceptor blockade. At 3 days-4 weeks after unilateral nerve section there were no signs of CGRP-, substance P- and NKA-immunoreactivity, and there was no vasodilation in response to tooth stimulation. The vasoconstrictor response was also absent during this period but at 4 weeks postoperatively a weak response was obtained and after 7 weeks the vasoconstrictor response had regained normal amplitude. At 7 weeks postoperatively, a large number of CGRP-positive fibres had reappeared and at 11 weeks the pattern of CGRP-immunoreactivity was normal. However, substance P- and NKA-immunoreactivity were not found at 7 or 11 weeks after surgery. Vasodilator responses appeared at 7 weeks, and showed normal amplitude at 11 weeks after the creation of the nerve lesion. The results show that during nerve regeneration, sympathetic vasoconstriction was regained earlier than neurogenic vasodilation in rat incisor teeth. The reappearance of neurogenic vasodilation after nerve injury was temporarily associated with the presence of CGRP-immunoreactivity in regenerating trigeminal afferent nerves.

Mandibular nerve neuropathy in sickle cell disease. Local factors.

An instance of permanent neuropathy that affected the mandibular nerve after a vaso-occlusive crisis in a patient with homozygous sickle cell disease and G6PD deficiency. A local factor of molar periapical inflammation may have provoked this phenomenon.

An anatomical study of the laterotrigeminal venous system.

The middle cranial fossa of 100 cadavers were dissected under stereoscopic loupe in order to identify and systematize the venous vessels located along the lateral margin of the trigeminal cave. The author found that at the sensitive root and trigeminal ganglion level a dural venous canal was present in most individuals examined and that the upper side of this canal communicated with the superior petrosal sinus. However, at the level of the lateral border of the intracranial segment of the mandibular nerve, venous lacunae were found to prevail, and these lacunae communicated with several other venous formations in the peritrigeminal region. The author concludes that the venous vascularization of this area constitutes a major risk in surgical interventions made in the middle cranial fossa. In addition, it is a relevant factor in the hemodynamics of the intracranial circulation.