lingual foramen lingual foramen the lingual foramen is a small midline opening on the posterior aspect of the symphysis of the mandible, just above the mental spine. the lingual foramen gives passage to a single small artery formed by the union of two branches of the sublingual arteries (each sublingual artery contributing a single branch). the small lingual foramen (black "hole" in lower portion of picture) as seen on a periapical radiograph of the anterior mandible.