Meckelian groove

Meckelian groove is a notable anatomical feature found in the mandible, or lower jawbone, of many vertebrates, including humans. It is named after Johann Friedrich Meckel, the Younger, who was a German anatomist that made significant contributions to the understanding of this structure. The Meckelian groove plays a crucial role in the development of the mandible and is associated with the Meckel's cartilage, which is a temporary cartilage bar from which the mandible is partly developed.

Structure

The Meckelian groove is located on the inner surface of the mandible. In early development, it houses the Meckel's cartilage, which serves as a template for the mandibular bone's growth. As development progresses, the cartilage is largely replaced by bone, but remnants can persist into adulthood in some species. In humans, the Meckel's cartilage does not ossify but contributes to the formation of the sphenomandibular ligament and the anterior ligament of the malleus in the middle ear.

Function

The primary function of the Meckelian groove is during embryonic development, where it guides the growth and development of the mandible. It ensures that the mandible forms correctly and attaches to the rest of the skull in the appropriate manner. The presence of Meckel's cartilage within the groove is essential for the normal development of the mandible, influencing its shape and size.

Clinical Significance

Abnormalities in the development of the Meckelian groove and Meckel's cartilage can lead to various craniofacial anomalies and disorders. These can include mandibulofacial dysostosis, also known as Treacher Collins syndrome, and Pierre Robin sequence, which involves a smaller than normal lower jaw (micrognathia), a tongue that is placed further back than normal (glossoptosis), and obstruction of the airways.

Evolutionary Significance

The Meckelian groove also has evolutionary significance. It is a feature present in the mandibles of many vertebrates, including those of some extinct species. The study of this groove and the associated Meckel's cartilage provides insights into the evolutionary changes in the structure and function of the jaw among different species.

See Also

• Mandible
• Meckel's cartilage
• Craniofacial
• Treacher Collins syndrome
• Pierre Robin sequence