The frontalis muscle is innervated by the cranial nerve VII( facial nerve) . Since the frontalis muscle attaches to the skin around the eyebrows, this muscle’s main function is to raise the eyebrows which also causes the skin of the forehead to wrinkle.
The frontalis muscle (Latin meaning ‘frontal belly’) is muscle which covers parts of forehead of the skull. Some sources consider the frontalis muscle to be a distinct muscle. However, Terminologia Anatomica currently classifies it as part of the occipitofrontalis muscle along with the occipitalis muscle.
In humans, the frontalis muscle only serves for facial expressions.
The frontalis muscle is supplied by the facial nerve and receives blood from the supraorbital and supratrochlear arteries.
The muscle has no bony attachments. Its medial fibers are continuous with those of the procerus; its immediate fibers blend with the corrugator and orbicularis oculi muscles, thus attached to the skin of the eyebrows.
The origin of a muscle refers to the location of the body where a muscle starts or begins. Therefore, the origin of the frontalis muscle is the galea aponeurotica, which is a fibrous layer that covers the top of the cranium and extends from the forehead to the back base of the skull. The frontalis muscle originates at the anterior, or front, of the galea aponeurotica, which is near the top of the forehead.
From the galea aponeurotica, the frontalis muscle extends down the forehead and attaches/ends at the eyebrows and upper nose. Specifically, the end of the frontalis muscle interdigitates, or blends, with the muscles of the eyebrows and nose,which include the orbicularis oculi muscle and the procerus muscle.
By right and left bellies from the skin of the eyebrow, with fibers extending down to interdigitate with orbicularis oculi and procerus
Nerve Supply :
In order for any muscle in the body to contract or move, it must receive electrical impulses from the brain, a process called innervation. Nerves throughout the body send these electrical impulses from the brain to muscles in the body and each muscle has a specific innervating nerve. The nerve that innervates the frontalis muscle is the cranial nerve VII, which is also known as the facial nerve VII.
Muscle Action :
Since the frontalis muscle begins near the front of the forehead and extends down to the eyebrows, this muscle is involved in several movements of these facial structures. Specifically, the frontalis muscle allows you to raise your eyebrows, wrinkle your forehead, and move your scalp posteriorly, or backward.
In Bell’s palsy Frontalis Muscle Commonly Paralysed.