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 Table of Contents  
Year : 2021  |  Volume : 10  |  Issue : 1  |  Page : 51-54

Coronoid Foramina in a Pediatric Mandible: An Incidental Finding of a Morphologic and Developmental Anatomic Variant as a Distinctive Documented Feature

1 Senior Consultant and Operational Head, Department of Pediatric Dentistry, Dental Health Care and Research Unit @ Gharonda, Hosmat Hospital, Hennur, Bangaluru, Karnataka, India
2 Clinical Director and Consultant, Department of Oral and Maxillofacial Surgery, Dental Health Care and Research Unit @ Gharonda, Hosmat Hospital, Hennur, Bangaluru, Karnataka, India

Date of Submission19-Oct-2020
Date of Decision29-Nov-2020
Date of Acceptance21-Dec-2020
Date of Web Publication27-Jan-2021

Correspondence Address:
S Ghousia
Dental Health Care and Research Unit @ Gharonda, HOSMAT Hospital, #1, Hennur Junction, Grace Town, Kalyan Nagar, Bengaluru - 560 043, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/NJCA.NJCA_58_20

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The new advancing technologies have created a storm in the long-existing canons of anatomic sciences with the bandwagon of recent anatomical discoveries such as the existence and identification of a bilateral foramen in the coronoid process of the mandible. The coronoid process being a thin flat triangular process varies in shape and size and gives attachment to the main muscles of mastication the temporalis and the masseter. The excitement of exploratory anatomic victory on mysteries related to the anatomy of the head-and-neck region specific to the coronoid process was further documented and elaborated as an incidental finding. The following manuscript presents an intriguing case of a pediatric patient aged 7 years with a morphologic variation of coronoid process with presence of foramina bilaterally along with few other variants, further attempting to emphasize its occurrence in the developmental years as a possibility of developmental variant trait.

Keywords: Anatomic variant, coronoid foramen, developmental variant, mastoid air cells, nutritional canal, pediatric variant

How to cite this article:
Ghousia S, Nyer Firdoose C S. Coronoid Foramina in a Pediatric Mandible: An Incidental Finding of a Morphologic and Developmental Anatomic Variant as a Distinctive Documented Feature. Natl J Clin Anat 2021;10:51-4

How to cite this URL:
Ghousia S, Nyer Firdoose C S. Coronoid Foramina in a Pediatric Mandible: An Incidental Finding of a Morphologic and Developmental Anatomic Variant as a Distinctive Documented Feature. Natl J Clin Anat [serial online] 2021 [cited 2023 Jan 29];10:51-4. Available from: http://www.njca.info/text.asp?2021/10/1/51/308120

  Introduction Top

The identification of the pediatric anatomic variants is immensely demanding, and unfortunately, there is a comparative insufficiency of literature detailing the appearance of the same. A foramen in the coronoid, a prominent bony structure in the mandible, has recently been documented and reported in a live adult human case. The unknown of these anatomical variations and their presence can have adverse implications with added complications in the performance of surgical procedures and cause a failure in the plan of anesthesia in dental and maxillofacial practice.[1]

Cone-beam computed tomography (CBCT) has probably been one of the most revolutionary innovations in the field of dentistry in the past decade, and it provides a novel platform for imaging of the maxillofacial area.[2] CBCT in dentistry has provided an imaging solution that has none of the projection errors associated with magnification and none of the superimposition problems associated with traditional panoramic imaging.[3] In addition, it has a wide range of tools such as three-dimensional (3D) reconstructions in any direction to permit accurate identification of landmarks. In the present case, both panoramic two-dimensional and 3D CBCT were used; the identification of the anatomic variant was reflected in landmark identification.[4]

  Case Report Top

A 7-year-old reported to our unit of Pediatric dentistry for complete oral rehabilitation post relocation in a new city for subsequent follow-up for oral health treatment needs. The patient presented with no significant medical, pre-natal, natal, or postnatal history. The initial investigatory panoramic (orthopantomagram [OPG]) radiograph was acquired to assess the treatment rendered during the previous dental visits by her dentist located in a different place. Informed consent was obtained from the patient and her parents for reporting.

Clinical findings

Dental caries in relation to 63, 64, 74, 75, 84, and 85 and root stumps in relation to 54 were noticed. The suggested treatment plan was the extraction of root stumps followed by band and loop space maintainer, restoration of carious teeth, and finally, pulpectomies and stainless-steel crowns were planned as per the lesion involvement.

Radiographic findings

Apart from routine dental carious lesion findings, the OPG revealed a unique and intriguingly unusual radiolucency in the coronoid processes bilaterally suggestive of coronoid foramina (CF) [Figure 1]. The same was informed to the parents and about the possibility of presence of anatomic variant foramina in the mandible and also about the local anesthetic procedures being a bit challenging during subsequent treatment protocols. Parents wanted to go ahead for further confirmatory investigations of the same for their child to update themselves of any possibility of anatomic variation. CBCT was hence acquired after due informed consent and the following observations were made:
Figure 1: Panoramic radiograph shows mixed dentition and unusual radiolucency in the coronoid processes bilaterally white dotted circles

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The 3D reconstruction of the CBCT scan confirmed the presence of CF bilaterally along with the presence of multiple emissary foramina over the left-sided infratemporal region of the sphenoid bone and an emissary foramen in the external auditory canal [Figure 2]. The multiplanar slices of the CBCT scan further confirmed the presence of CF bilaterally in sagittal and axial sections of both right and left sides. The sagittal and axial images of the right side revealed the presence of an accessory branching canal along with the coronoid canal within the coronoid process which in most likely possibility is a nutritional canal. There was also extensive pneumatization of the mastoid air cells noted [Figure 3]. Similarly, the multiplanar slices in a sagittal and axial orientation of the left side revealed the presence of CF along with the extensive pneumatization of the mastoid air cells [Figure 4].
Figure 2: Three-dimensional reconstructed images of (a) right-sided lateral view showing co condyle, coronoid foramen red arrow, e external auditory meatus, m mastoid process and (b) left-sided lateral view showing emissary foramen of the auditory canal blue arrow, m mastoid process, v vertebrae, emissary foramina over the infratemporal surface of the sphenoid bone dark blue arrows, coronoid foramen red arrow and co condyle

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Figure 3: Multiplanar slices of right-sided cone-beam computed tomography (a) sagittal view showing pneumatized mastoid process blue arrow, e external auditory meatus, Coronoid canal along with an accessory branching canal red arrow and (b) axial view showing co condyle, m mastoid air cells, coronoid foramen red arrow

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Figure 4: Multiplanar slices of left-sided cone-beam computed tomography (a) axial view showing m mastoid air cells, co condyle, coronoid foramen green arrow and (b) Sagittal view showing extensive pneumatization of mastoid air cells red arrow, e external auditory meatus, coronoid foramen green arrow

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  Discussion Top

As the interpretation of investigatory imaging in pediatrics is more challenging than the interpretation of adult investigatory reports, it is of utmost importance to be familiar with normal anatomic variations, developmental anomalies, normal bone appearance, and growth plane maturation as well as pitfalls related to different imaging artifacts. Therefore, the decoding of pediatric oro-maxillofacial scans can be challenging even for the most experienced pediatric radiologists and pediatric oral maxillofacial surgeons.[2],[3],[4],[5]

It is not very often in the pediatric oro-maxillofacial practice that a clinician comes across anatomic variations as incidental findings in panoramic radiographs. These are often mistaken for true underlying pathology, sometimes resulting in redundant additional imaging or invasive procedures. According to a study from 1898, the anatomical variations are errors in the embryologic developmental timing or persistence of normally obliterated structures.[6] The possible hypothesis as understood from the exhaustive comparative morphology and the available literature[1] suggests that the anatomic variation is a possible reflection of what is found in other mammals, one such hypothesis is the phylogenetic co-relation. The CF bilaterally had never been observed in humans or in osteology studies until recently, as it was considered a feature of proboscidean fossils excluding elephantines.[1],[7] It was Ferretti and Debruyne in 2011 who interpreted a specimen of “Elephas Maximus” as possessing a coronoid foramen which “merged with the alveolus of the distal most erupting molar” to be in confluence to form a coronoid canal.[8],[9] This coronoid canal was first identified as a synapomorphy of Paenungulates by Tassy and Shoshani in 1988.[10]

The pediatric mandible is the depository for the developing teeth. These developing tooth buds always add complexity to the diagnosis of accessory foramina or accessory canals. Although accessory foramina are considered constant structures in a pediatric mandible, majority location of such variations in foramina are in the anterior segment. Sometimes, the variations can occur with the mandibular canal such as bifid and trifid mandibular canals, the initial classification of the mandibular canal described only four types with a later addition of the fifth type. Type I is a retromolar canal in the retromolar region, Type 2 is a dental canal the end of which reaches the root apex of the second and third molar, Type 3 is a branch arising from the superior wall of the mandibular canal, Type 4 is buccal or lingual canal arising from the buccal or lingual surface of the main mandibular canal, and finally, Type 5 is trifid canal variant.[7]

It was also postulated that a critical period occurs in the development of the primate cerebrum between the 3rd and 4th months of fetal life. About this time, the cerebrum takes that step which lifts it beyond the quadruped stage and places it upon the higher primate platform. Previous to this change, the cerebrum presents a form similar to that of a quadruped, while the occipital lobe takes shape, and the cerebrum assumes a form and an outline characteristic of man and the apes. A variation may occur in man which produces a structural character identical with what is seen normally in another animal group. This variation may be truly atavistic, but for all that it does not follow, as a matter of course, it is genetically related to the corresponding character in the animal group. This possibility must be always borne in mind in determining the proper value of an anatomical variation.[6]

The present case report investigations and radiographs reveal the presence of multiple emissary foramina in the temporal surface of the sphenoid bone, emissary foramen in the auditory canal, and foramina in the coronoid processes bilaterally, the kind of variations which have never been reported or documented in the literature in a pediatric live individual. These findings, however, are in semblance to the recent discovery of CF of the mandible.

Clinical significance/importance

The presented anatomic variant is the first of its kind to be documented in a live pediatric patient. The presence of such a variation in the mandible can lead to a challenge in achieving proper anesthesia for regular dental procedures, the treatment plan may also need to be altered in case of pediatric jaw surgeries considering the presence of neurovasculature occupying such foramina. Moreover, there is a possibility of unexpected complications arising in terms of bleeding and postsurgical paraesthesia which may occur due to the involvement of the contents of such foramina. Therefore, it is imperative to be informed or have knowledge of such anatomic variations in pediatric patients.

  Conclusion Top

Oro-maxillofacial radiologic evaluation of the pediatric mandible can be challenging because of the growth pattern changes, normal anatomic variants, and injuries that are unique to children. Familiarity with anatomic variants is also important for correct image interpretation. This case report further suggests that the clinicians should be aware of the possibilities of the anatomic variants from the earlier ages of life and keep their parents informed about the same, so it is mentioned to future treatment collaboration team of oral surgeons, radiologists if any in the later days of their life if the patient is required to go through any invasive surgical procedures in the oral–maxillofacial region.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Firdoose Chintamani Subhan N. Bilateral 'coronoid foramina' with accessory foramina on the 'lateral aspect of ramus' of mandible: An unseen variance discovery in humans. Surg Radiol Anat 2018;40:641-6.  Back to cited text no. 1
Agrawal JM, Agrawal MS, Nanjannawar LG, Parushetti AD. CBCT in orthodontics: The wave of future. J Contemp Dent Pract 2013;14:153-7.  Back to cited text no. 2
McWilliam JS, Welander U. The effect of image quality on the identification of cephalometric landmarks. Angle Orthod 1978;48:49-56.  Back to cited text no. 3
Houston WJ, Maher RE, McElroy D, Sherriff M. Sources of error in measurements from cephalometric radiographs. Eur J Orthod 1986;8:149-51.  Back to cited text no. 4
Waitzman AA, Posnick JC, Armstrong DC, Pron GE. Craniofacial skeletal measurements based on computed tomography: Part II. Normal values and growth trends. Cleft Palate Craniofac J 1992;29:118-28.  Back to cited text no. 5
Cunningham DJ. The significance of anatomical variations. J Anat Physiol 1898;33:1-9.  Back to cited text no. 6
Nyer Firdoose CS. Concurrent 'coronoid foramen' with trifid mandibular canal in a live human: CBCT exploration of a unilateral variant. Eur J Anat 2020;24:229-34.  Back to cited text no. 7
Ferretti MP, Debruyne R. Anatomy and phylogenetic value of the mandibular and coronoid canals and their associated foramina in proboscideans (Mammalia). Zool J Linn Soc 2011;161:391-413.  Back to cited text no. 8
Tassy P, Shoshani J. The Tethytheria: Elephants and Their relatives. In the Phylogeny and Classification of the Tetrapods, Mammals. Oxford Clarendon Press Syst Assoc 1988;35B:283-315.  Back to cited text no. 9
Gunduz K, Serindere G, Avsever H, Orhan K. A detailed CBCT study of 'coronoid foramina' and accessory foramina of the mandible: A unique anatomic variation. Acta Clin Croat 2019;58:693-700.  Back to cited text no. 10


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]


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