Korean J Phys Anthropol.  2014 Jun;27(2):65-70. 10.11637/kjpa.2014.27.2.65.

Morphometric Study of the Retromolar Triangle and Foramen in Korean Mandibles

• Park MK
• Ryu SJ
• Kim SH
• Kwak HH

• KMID: 1917125
• DOI: http://doi.org/10.11637/kjpa.2014.27.2.65

Abstract

It has been known that the retromolar foramen is a rare anatomic variation observed in the retromolar triangle, a small triangular shaped region posterior to the mandibular third molar. Due to the neurovascular bundle passing through the retromolar foramen, this anatomical structure must be kept in mind during surgical approaches regarding the retromolar area and mandible. Therefore, the authors investigated the morphology of retromolar triangle and the existence and location of retromolar foramen in Korean. And these results were compared with that of other races. We used 308 sides of 154 Korean dry mandibles, unknown gender and age. The retromolar triangle presented predominantly a triangular shape (84.1%), and the maximum height and width were 13.7 mm and 7.1 mm, respectively. In 144 of the 308 sides, the retromolar foramen was observed (46.8%). The existence of the retromolar foramen was seen the same frequency in both sides, and based on a midsagittal line of the retromolar triangle, the retromolar foramen located in more buccal side (75%) than lingual side. The mean distance between the retromolar foramen and the distal edge of the last tooth were found to be 10.3 mm and 6.9 mm, respectively for the second and third molars. According to the present study, the northeast Asians including Korean population show the highest rate of the incidence of the retromolar foramen than other races. The findings suggest that practitioners should take the retromolar foramen into account in surgical procedures involving the retromolar area to protect the patient from the complications such as bleeding or nerve damage.

Keyword

Koreans; Mandible; Retromolar triangle; Retromolar foramen

MeSH Terms

Anatomic Variation
Asian Continental Ancestry Group
Continental Population Groups
Hemorrhage
Humans
Incidence
Mandible*
Molar, Third
Tooth

Figure

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  Fig. 1. Classifications of the RMT according to the shape. (A) Triangular shape (84.1%), (B) Drop shape(9.3%), and (C) Tapering shape (6.6%).

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  Fig. 2. Photographs showing the RMF(arrowheads). (A) RMF located in the RMT and on the lingual side of the midsagittal line of RMT,(B) RMF located in the RMT and on the midsagittal line of RMT, and (C) RMF located out of the RMT and on the buccal side of the midsagittal line of RMT.

Reference

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