Which arch is formed by segmented mesoderm associated with occipital somites?

Which arch is formed by segmented mesoderm associated with occipital somites?

• A. First arch
• B. Second arch
• C. Third arch
• D. Fourth arch

Answer: (D)

Pharyngeal arches develop from a mix of neural crest and paraxial mesoderm, with the mesoderm portion lined up along the head and neck region coming from somites and somitomeres. The arches that follow the first two derive their mesoderm from the occipital region’s somites, so the arch formed by segmented mesoderm associated with occipital somites is the fourth arch. This arch contributes to structures like the laryngeal cartilages and pharyngeal constrictors, and its nerve supply comes from the superior laryngeal branch of the vagus.

Pharyngeal arches develop from a mix of neural crest and paraxial mesoderm, with the mesoderm portion lined up along the head and neck region coming from somites and somitomeres. The arches that follow the first two derive their mesoderm from the occipital region’s somites, so the arch formed by segmented mesoderm associated with occipital somites is the fourth arch. This arch contributes to structures like the laryngeal cartilages and pharyngeal constrictors, and its nerve supply comes from the superior laryngeal branch of the vagus.