Which arch forms the occipitalis?

Which arch forms the occipitalis?

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

Answer: (B)

The occipitalis is part of the muscles of facial expression, which come from the second pharyngeal arch. This arch is associated with the facial nerve and gives rise to many facial expression muscles, including the two bellies of the occipitofrontalis (frontalis and occipitalis). That makes the second arch the source for the occipitalis. In contrast, the first arch forms muscles of mastication, the third arch contributes stylopharyngeus, and the fourth and sixth arches give other pharyngeal and laryngeal muscles, not the facial-expression group that includes the occipitofrontalis.

The occipitalis is part of the muscles of facial expression, which come from the second pharyngeal arch. This arch is associated with the facial nerve and gives rise to many facial expression muscles, including the two bellies of the occipitofrontalis (frontalis and occipitalis). That makes the second arch the source for the occipitalis.

In contrast, the first arch forms muscles of mastication, the third arch contributes stylopharyngeus, and the fourth and sixth arches give other pharyngeal and laryngeal muscles, not the facial-expression group that includes the occipitofrontalis.