The significant demand for the inferior alveolar nerve block (IANB) in dental practice necessitates a deep understanding of the anatomy of the pterygomandibular space (PMS) for the clinician. The problems of complications and inefficiency of IANB remain relevant and may be due to both a violation of the technique of anesthesia, and the variability of the location of structures in the space or its size (Iwanaga et al., 2018, Tijanić et al., 2020).

The pterygomandibular space is mainly limited by connective tissue and muscles, containing several neurovascular structures. It has a triangular shape and is limited by the medial surface of the mandibular branch from the outside. The medial pterygoid muscle and the fascia associated with it limit the space medially, and the lateral pterygoid muscle - from above. Of particular importance for local anesthesia is the fact that the inferior alveolar nerve, artery and vein, together with the lingual nerve, cross the PMS (Khoury et al., 2011, Tomaszewska et al., 2019).

Fig. 1 shows the structures of the pterygomandibular space and the lateral region of the face.

The direct IANB technique involves inserting a needle into the pterygomandibular space by injection. The aim of the technique is to inject a local anesthetic solution just above the tip of the mandibular lingula. Diffusion of the local anesthetic solution blocks the nerve just before it enters the mandibular foramen.

To study the pterygomandibular space, methods of radiation diagnostics, such as radiography and computed tomography, were used. As it is said (Keil C., 2022), CBCT should be the gold standard for evaluating anatomical variations. Radiographs are a two-dimensional summation of three-dimensional structures, which makes them useful for determining bone relationships in a plane perpendicular to the X-ray source. Taking into account the peculiarity of the technology, the possibility of tracking the course of the diffusion of the local anesthetic during the introduction of IANB is available only when it is mixed with a contrast media. To analyze the dynamics of diffusion of local anesthetics, computed tomography is used (Okamoto et al., 2000, Smirnov et al., 2016). However, more research is needed to expand knowledge of diffusion pathways, volume, and structural relationships in the PMS, as there is insufficient research data available in the current literature.

The aim of our study was to determine the volume of the pterygomandibular space depending on the shape of the skull, face and mandible using computed tomography technology.