In the common form the rim is V-shaped, with a groove separating the anterior and posterior parts.
In the horizontal-oval form there is no groove, and the rim is horizontally oriented and oval in shape, the anterior and posterior parts connected.
Rarely, a bifid inferior alveolar nerve may be present, in which case a second mandibular foramen, more inferiorly placed, exists and can be detected by noting a doubled mandibular canal on a radiograph.[3]
Local anaesthetic can be injected around the mandibular foramen to anaesthetise the mandibular nerve, and thereby the mandible the lower teeth on that side, and some skin on the lower face.[1]
Other animals
The mandibular foramen can be found in other mammals, such as horses.[2]
Additional images
View from behind of the mandibular foramina (red).
cranialnerves at The Anatomy Lesson by Wesley Norman (Georgetown University) (V)
Nicholson, Michael L. (1985). "A study of the position of the mandibular foramen in the adult human mandible". The Anatomical Record. 212 (1): 110–2. doi:10.1002/ar.1092120116. PMID4073538. S2CID11785956.
Hetson, George; Share, Jack; Frommer, Jack; Kronman, Joseph H. (1988). "Statistical evaluation of the position of the mandibular foramen". Oral Surgery, Oral Medicine, Oral Pathology. 65 (1): 32–4. doi:10.1016/0030-4220(88)90187-9. PMID3422395.
Smith, Fred H. (1978). "Evolutionary significance of the mandibular foramen area in neandertals". American Journal of Physical Anthropology. 48 (4): 523–31. doi:10.1002/ajpa.1330480412. PMID96699.