Vascular channels are often found in the midline and lateral to the midline of the mandible. Although the lingual foramen was found in 99% of dissections it was seen in less than 49% of peripaical films . Here is patient I saw recently.One can see the lingual foramen clearly on the CT slice, as well as the periapical film and also if you look carefully at the OPG.
The lingual foramen harbors an artery that is an anastomosis of right and left sublingual arteries. This tiny vessel (0.4 to 1.5mm) has been implicated in serious hemorrhage and rarely fatalities. one should be aware of the presence of this vessel and avoid it when possible.
For the periapical and the opg image click on the title of this post