Bilateral incomplete mandibular canals: an embryological analysis of their possible etiology

This study aims to report a previously undocumented anatomical variation of the mandible and investigate its developmental origin using embryological analysis.

Anatomical inspection and computed tomography were performed on a dried human mandible from a male cadaver of unknown age. Additionally, serial histological sections from a Carnegie Stage 23 human embryo were reconstructed in 3D model to examine the spatial relationships between the developing mandible and surrounding structures.

The mandibular canal exhibited breaching of the medial wall into the lingual cortex on both sides. Computed tomography confirmed that the canals originated from the mandibular foramen and gave rise to the mental foramina at the medial third of the mandible. These defects were found along with a left-sided Stafne bone cavity. Embryological analysis revealed a close spatial proximity between the developing mandible, the inferior alveolar nerve, and the salivary glands, supporting the hypothesis that incomplete ossification could result from variant nerve positioning or glandular entrapment.

This study presents rare anatomical variations of the mandibular canal and their possible developmental mechanism. These findings have implications for radiological interpretation and surgical planning involving the mandible.