Embryonic Development and Comparative Anatomy of the Mandible

Shaibu Mohammed Atabo,Abubakar Abubakar Umar,Sani Abdullahi Shehu,Adamu Abdul Abubakar

doi:10.28991/scimedj-2021-0301-3

Shaibu Mohammed Atabo, Abubakar Abubakar Umar + Show 2 more

Open Access

https://doi.org/10.28991/scimedj-2021-0301-3

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Abstract

Objective: This study was designed to determine the ossification time and pattern of the mandible. Methodology: Three hundred and fifty (350) wasted fetuses consisting of 70 Balami, 140 each of Uda and Yankasa breeds whose crown vertebral rump length ranged from 3.0-15 cm were used. The fetuses were processed using the Alizarin technique and the mandible was dissected from the head for stereography. Result: The result revealed that the first part of the mandible to develop was the body and mental foramina at the 42nd–44th days of gestation while the coronoid process, rami, and condyloid process develop later at different time points. In addition, the mandibular foramina remained undeveloped in all age groups. Interestingly, the mandibular canal began ossification earlier in the Yankasa breed compared to other breeds. It was shown to arise from a cartilaginous tissue at the medial and lateral surfaces of the body and dorsally remained opened and undifferentiated from the teeth alveoli of the lower jaws in the 7 age groups. Conclusion: It was therefore concluded that the mandible arises from three ossification centres at the body, rami, and coronoid process. These segments develop at different time intervals in the three breeds of sheep with Yankasa mandible ossifying and progressing faster than in Balami and Uda. Doi: 10.28991/SciMedJ-2021-0301-3 Full Text: PDF

Highlights

The mandible is the largest and strongest bone of the skull
The crown vertebral rump length (CVRL) of the fetal samples were obtained with a measuring tape, extending from the anterior fontanel and following the vertebral column down to the base of the tail to determine the gestational ages in days using the formula: X=2.1(Y+17) where X= Gestational Age in days and Y=Crown Vertebral Rump Length [16], based on their age, they were classified into seven age groups ranging from 42nd – 67th days of gestation
The different parts of the mandible in the three breeds of sheep developed at different time intervals from different ossification centres

Summary

Introduction

The mandible is the largest and strongest bone of the skull. It forms the lower jaw and accommodates the lower incisors, premolar, and molar teeth in ruminants [1]. The mandible articulates with the temporal bone to form the only movable joint of the skull referred to as the temporo-mandibular joint which plays a major role in apprehension and chewing [2, 3]. Ahmed and Mahmood (2011) [5] and Ahmed (2003) [6] have previously examined the development of the mandible in Iraqi breed of sheep and Iraqi Black goats respectively. Details on the developmental anatomy of the mandible are vital in diagnosing and understanding the pathogenesis of oral disorders such as malocclusion, prognathism, and brachignatia [10].

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