Osteometric and radiological study of the mandibular notch / Estudio osteométrico y radiológico de la incisura mandibular

The mandibular notch is located on the superior margin, between two prominent processes of the mandibular ramus, the coronoid and condylar processes. The mandibular notch permits the entry of the masseteric artery, vein and nerve to the deep surface the masseteric muscle. Literary reports documented variations in both, the shape and size of the mandibular notch. Therefore, this study aimed to document the morphology and morphometry of the mandibular notch in the South African Black and Indian population groups and to determine their relationship to sex, age and race (if any). The morphometric and morphological parameters of the mandibular notch were measured and assessed in 149 digital panoramic radiographs and 51 dry mandible specimens (n=400) belonging to the South African Black African and Indian population groups. A combination of classification schemes by Mohammad et al. (2012) and Shakya et al. (2013) were adopted to assess the morphology of the mandibular notch. The morphometric parameter was measured using the Dicom x-ray viewer and a digital vernier caliper. Each of the morphometric and morphological parameters were statistically analyzed using SPSS, to determine if a relationship existed between the afore-mentioned parameters and sex, age and race. This study recorded the round shaped mandibular notch to be the most prevalent type in both sexes with a combined incidence of 44.2 %. The length of the mandibular notch was reported to be greater in males than females and concurred with previous studies. However, the selected South African group displayed a smaller mandibular notch than the Japanese and Chinese population groups. Furthermore, this study documented population differences among the South African population group, as the Black African population group showed a wider mandibular notch than the Indian population group. This suggests that population-specific differences may exist for both the morphological and morphometric parameters of the mandibular notch. However, only a statistically significant relationship between the length of the mandibular notch with age and race was documented. The mandibular notch may be of clinical significance to maxillofacial surgeons for surgical and reconstructive procedures, in addition it may also aid forensic anthropologists in the identification of unknown remains.

La incisura mandibular se encuentra en el margen superior, entre dos procesos importantes de la rama mandibular, el proceso coronoides y el proceso condilar. La incisura mandibular permite la entrada de la arteria, la vena y el nervio masetérico en la superficie profunda del músculo masetero. En la literatura se han documentado variaciones tanto en la forma como en el tamaño de la incisura mandibular. Este estudio tuvo como objetivo documentar la morfología y la morfometría de la incisura mandibular en los grupos de población de negros e indios sudafricanos y determinar su relación con el sexo, la edad y la raza. Los parámetros morfométricos y morfológicos de la incisura mandibular se midieron y evaluaron en 149 radiografías panorámicas digitales y 51 especímenes de mandíbula seca (n = 400) pertenecientes a los grupos de población sudafricana negra e india. Una combinación de esquemas de clasificación de Mohammad et al. (2012) y Shakya et al. (2013) fueron adoptados para evaluar la morfología de la incisura mandibular. El parámetro morfométrico se midió utilizando el visor de rayos X Dicom y un calibrador Vernier digital. Cada uno de los parámetros morfométricos y morfológicos se analizaron estadísticamente utilizando el software SPSS, para determinar si existía una relación entre los parámetros mencionados anteriormente y el sexo, la edad y la raza. Este estudio registró la incisura mandibular de forma redonda como el tipo más prevalente en ambos sexos, con una incidencia de un 44,2 %. Se informó que la longitud de la incisura mandibular es mayor en hombres que en mujeres y coincidió con estudios anteriores. Sin embargo, el grupo sudafricano seleccionado mostró una incisura mandibular más pequeña que los grupos de población japoneses y chinos. Además, se documentó las diferencias de población entre el grupo de Sudáfrica, ya que el grupo de población negra de África mostró una incisura mandibular más amplia que el grupo de la población India. Esto sugiere que pueden existir diferencias específicas de la población para los parámetros morfológicos y morfométricos de la incisura mandibular. Sin embargo, solo se documentó una relación estadísticamente significativa entre la longitud de la incisura mandibular con la edad y la raza. La incisura mandibular puede ser de importancia clínica para los cirujanos maxilofaciales en procedimientos quirúrgicos y reconstructivos; además, también puede ayudar a los antropólogos forenses en la identificación de restos desconocidos.

A Morphometric Study on the Mandibular Foramen and the Lingula in Korean / 체질인류학회지

Interest in the correction of jaw deformities has increased due to the development of techniques and instruments of jaw operation. The accurate position of the mandibular foramen and lingula is important for the prevention of the complications and successful inferior alveolar nerve block. This study was conducted on 104 dried mandibles (65 males, 39 females) from Korean cadaver. The positions of the mandibular foramen and lingula were measured on the coronoid notch, occlusal plane, mandibular notch, gonion, koronoid and kondylion. The structures of the mandibular foramen and lingula were determined and the thickness of ramus and the angle of mandible were measured. Independent t-tests and paired t-tests were performed to determine the statistically significant difference. The results as follows; The line between coronoid notch and posterior border of ramus was located on the same level with the tip of lingula in 42.2% of the cases, and in between the mandibular foramen and the tip of lingula in 33.8% of the cases. The occlusal plane was located on the level between the mandibular foramen and the tip of lingula in 47.7% of cases, and on the same level with the tip of lingula in 35.6% of the cases. The line between lower end of the mandibular notch to inferior border of the mandible, in parallel to the posterior border of the mandibles, met the tip of lingula in 55.8% of the cases. The mandibular foramen was located posteriorly to the midpoint on the anteroposterior (AP) width of the ramus. It was located at 57.3% of AP width from the coronoid notch and 56.5% from the occlusal plane. The mandibular foramen and the tip of lingula were located superiorly to the midpoint on the vertical height of the ramus, on the 48.5% and 35.7% of vertical distance from the coronoid notch, respectively. The mandibular foramen was located at 40% of the length on the line from the gonion to the koronion. The results of this study will provide important morphometric information to prevent the complications in mandibular surgery and also provide the basis for the development of the new techniques.