Question

The corticobulbar innervation of facial motoneurons to muscles of the upper face is bilateral. Which muscles are used to wrinkle the forehead and shut the eyes?

1) Muscles of mastication
2) Muscles of facial expression
3) Muscles of the tongue
4) Muscles of the neck

Answer 1

The muscles used to wrinkle the forehead and shut the eyes are the muscles of facial expression, including the orbicularis oculi and frontalis. The corticobulbar innervation of facial motoneurons to these muscles is bilateral.

Step-by-step explanation:

The muscles used to wrinkle the forehead and shut the eyes are the muscles of facial expression. These muscles include the orbicularis oculi, which closes the eye, and the frontalis, which moves the forehead. The corticobulbar innervation of facial motoneurons to these muscles is bilateral, meaning that signals from the brain are sent to both sides of the face to control these movements.