Occurrence of the Retromolar Foramen in Dry Mandibles of South-Eastern Part of India: A Morphological Study with Review of the Literature

Abstract

The retromolar foramen (RMF) is a rare anatomical structure situated in the retromolar fossa behind the third molar tooth. When it is present, the foramen is connected with the mandibular canal and is believed to transmit neurovascular structures that provide accessory source to the mandibular molars and the buccal area. Reports from the literature show that the presence of RMF could pose a challenge in complete blockage of the inferior alveolar nerve during mandibular surgeries. We report the incidence of retromolar foramen from ninety-four dry mandibles of south-eastern part of Karnataka State, India. The foramen was observed in 11 mandibles out of 94 included in the study (11.7%). In three mandibles, the foramen was present bilaterally (3.2%) and in three it was on the left side (3.2%) and in five it was on the right side (5.3%). For the first time, we also measured the dimensions of the retromolar area and distance of the foramen from third molar tooth to understand its risks during the surgical extraction of the lower third molar tooth. A thorough review of the literature has also been done to compare the present findings with the studies reported from the various populations.

Investigation of the Prevalence of Retromolar Canals: A Cone Beam CT Study

“…The content of the RMC has been evaluated in cadaveric, radiologic studies and clinical biopsies (Potu et al, 2014). The RMC has a neurovascular bundle which is found to contain predominantly thin myelinated nerve fibers, numerous venules and arterioles covered by collagen bundle fibres and a little amount of adipose tissue (Alves & Deana, 2015;Capote et al, 2015;Han & Park;Lizio et al;Motamedi et al;Park et al;Potu et al).…”

“…The RMC has a neurovascular bundle which is found to contain predominantly thin myelinated nerve fibers, numerous venules and arterioles covered by collagen bundle fibres and a little amount of adipose tissue (Alves & Deana, 2015;Capote et al, 2015;Han & Park;Lizio et al;Motamedi et al;Park et al;Potu et al). The artery in the RMC is the branch of inferior alveolar artery and the nerve derived from the inferior alveolar nerve (Kodera & Hashimoto, 1995;Capote et al).…”

A study on the incidence of retromolar foramen in South Indian adult dried human mandibles and its clinical relevance

“…The mean diameter and distance of retromolar foramen from posterior border of socket for 3 rd molar, anterior border of ramus of the mandible of the present study is compared with earlier studies [10][11][12]14 and represented in Table 4.…”

“…The mean distance of retromolar foramen from the posterior border of socket for 3 rd molar tooth and anterior border of ramus of mandible were 6.15 mm (2.23-12.10) and 8.02 mm (3.24-13.12) mm respectively ( Table 2). [7][8][9][10][11][12][13][14] and is summarized in Table 3. The highest incidence was reported by Narayana (21%) and the lowest by Shantaram (4.35%).…”

Redescription of the argyrolagid Microtragulus bolivianus (Metatheria, Polydolopimorphia, Bonapartheriiformes) based on new remains from Northwestern Ar

“…Small foramina open in the posterior end of this concavity, clearly visible in Anargyrolagus (Goin and Abello, 2013, figure 4.17), Argyrolagus scagliai (Simpson, 1970a), A. palmeri (Kraglievich, 1931), A. parodii (Rusconi, 1933), and Microtragulus bolivianus (Hoffstetter and Villarroel, 1974; this paper). These openings, called the retromolar foramina, are also present in some groups of mammals such as abderitids (Rusconi, 1933;Abello and Rubilar-Rogers, 2012, figure 6.4) and humans (Schejtman et al, 1967;Kumar Potu et al, 2014). In modern mammals the retromolar foramina are related with the mandibular canal that carries the inferior alveolar nerve and vessels (Schejtman et al, 1967).…”