ROLE OF MECKEL'S CARTILAGE IN THE DEVELOPMENT AND GROWTH OF THE RAT MANDIBLE

¹ Departments of Oral Pathology and Histology, University of Illinois College of Dentistry, Chicago, Ill.

This study is based on a serial histologic investigation of heads of 41 ia and 43 normal rats ranging in age from 13 days insemination to 30 days after birth. The findings were:

1. Right and left Meckel's cartilages begin to differentiate independently in the branchial mesenchyme at 13 days insemination age. They grow forward and inward to meet in the midline to form the rostral process.

2. Prior to the formation of the squamomandibular articulation, growth at the posterior end of Meckel's cartilages serves to cause a downward and forward shift of the mandibular process and the mandible. Growth in the rostral process serves to cause a forward growth of the mandibular process and mandible, and to widen the distance between right and left mandibles.

3. After the formation of the squamomandibular articulation, the posterior part of Meckel's cartilage degenerates but does not form the sphenomandibular ligament. The anterior part undergoes endochondral ossification and serves to cause a forward growth of the right and left mandibles, and to increase the transverse distance between them.

4. The otic part of Meckel's cartilage is separated from the mandibular part at 6 days of age.

This article has been cited by other articles:

				L Shum, Y Sakakura, P Bringas, W Luo, M. Snead, M Mayo, C Crohin, S Millar, Z Werb, S Buckley, et al. EGF abrogation-induced fusilli-form dysmorphogenesis of Meckel's cartilage during embryonic mouse mandibular morphogenesis in vitro Development, January 7, 1993; 118(3): 903 - 917. [Abstract] [PDF]