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.

Societal change through an increase in knowledge and accessibility of education as well as a push for autonomy has contributed to a shift in the balance of power from clinician to patient (especially in the last 20 years). This drive for personal autonomy has seen a shift from medical paternalism, a consequence of ignorance, to personal autonomy, a continuously evolving by-product of 17th century liberalism as expressed and facilitated by access of information. Consequently, patient-centred care has become the new standard for health care involving a two-way communication process of shared information and informed decision-making. At its centre is the patient's right to accept or decline treatment recommended by a clinician, be it detrimental or beneficial. Clinicians must recognize and appreciate this shift to patient-centred care and its legal ramifications.