Applied anatomy of the pterygomandibular space: improving the success of inferior alveolar nerve blocks

Abstract

A thorough knowledge of the anatomy of the pterygomandibular space is essential for the successful administration of the inferior alveolar nerve block. In addition to the inferior alveolar and lingual nerves, other structures in this space are of particular significance for local anaesthesia, including the inferior alveolar vessels, the sphenomandibular ligament and the interpterygoid fascia. These structures can all potentially have an impact on the effectiveness of local anaesthesia in this area. Greater understanding of the nature and extent of variation in intraoral landmarks and underlying structures should lead to improved success rates, and provide safer and more effective anaesthesia. The direct technique for the inferior alveolar nerve block is used frequently by most clinicians in Australia and this review evaluates its anatomical rationale and provides possible explanations for anaesthetic failures.Keywords: Inferior alveolar nerve block, dental anaesthesia, mandibular nerve, sphenomandibular ligament, lingual nerve.Abbreviations and acronyms: IAA = inferior alveolar artery; IAN = inferior alveolar nerve; IANB = inferior alveolar nerve block; IAV = inferior alveolar vein; LN = lingual nerve; PVP = pterygoid venous plexus.

A basic review on the inferior alveolar nerve block techniques

“…Radiographic studies by Okamoto et al ., on the diffusion of local anesthetic in the anterior technique revealed that the local anesthetic solution spread rapidly in the pterygomandibular space and also reached the inferior alveolar nerve from the site anterior to the mandibular foramen, a region containing no large vessels or nerves. [2930]Other alternative techniques: Other available techniques target the mandibular nerve branches rather than only the inferior alveolar nerve; these include approaches described by Gow-Gates, Vazirani/Akinosi's closed mouth, and Fischer's three stage technique;[2425] all three techniques need a highly skilled operator and are rarely used by dentists in Saudi Arabia, but may be a common practice in other countries. …”

“…Radiographic studies by Okamoto et al ., on the diffusion of local anesthetic in the anterior technique revealed that the local anesthetic solution spread rapidly in the pterygomandibular space and also reached the inferior alveolar nerve from the site anterior to the mandibular foramen, a region containing no large vessels or nerves. [2930]…”

Prevalence and location of accessory foramina in the human mandible

“…The inferior alveolar nerve (IAN) is the largest branch of the posterior division of the mandibular nerve and is the only one containing sensitive fibers and motor fibers. The IAN enters the mandible through the mandibular foramen and crosses the body of the mandible through the mandibular canal until it reaches the apex of the second premolar, where it is divided into two terminal branches: the mental nerve, which exits through the mental foramen, and the incisive nerve, which continues its journey to the anterior mandible [1].…”

Arched Needle Technique for Inferior Alveolar Mandibular Nerve Block

“…A thorough knowledge of the anatomy of the pterygomandibular space is essential for the successful administration of the inferior alveolar nerve block. Greater understanding of the nature and extent of variation in intraoral landmarks, altered nerve physiology in infection and histological understanding of the underlying structures should lead to improved success rates, and provide safer and more effective anaesthesia [9]. In advent bending of the needle within the oral tissues should be avoided to achieve better success rates with an intraoral anaesthetic technique.…”