Anatomy & Organs

Musculus occipitofrontalis – structure, function & diseases

Musculus occipitofrontalis

The musculus occipitofrontalis is a skin muscle made up of the musculus occipitalis and musculus frontalis , which belongs to the mimic musculature. The muscles raise and lower the eyebrows to frown or tighten the brow . With lesions of the facial nerve , paralysis of the occipitofrontalis muscle occurs.

What is the occipitofrontalis muscle?

A group of muscles is known as the musculi epicranii, which is assigned to the mimic musculature and lies close to the skull . The muscle group attaches to the galea aponeurotica. Different muscles belong to the musculi epicranii, for example the musculus frontalis and the musculus occipitalis. The former is a skin muscle.

Together with the musculus occipitalis, it is called the musculus occipitofrontalis or, in the German translation, the back of the head and forehead muscle. The two muscles are innervated by the Nervus Facialis, which controls the entire musculature of facial expressions . The two bellies of the musculus occipitofrontalis lie at opposite poles of the skull. The galea aponeurotica connects the two parts. Synonymous terms for the two muscle bellies of the musculus occipitofrontalis are the terms venter frontalis and venter occipitalis.

Anatomy & Structure

The venter frontalis originates at the supraorbital margo of the frontal bone and near the glabella. The muscle radiates fiber strands into the facial muscles in the immediate vicinity and is thus connected to the musculus procerus, corrugator supercilii and orbicularis oculi.The opposing muscle belly of the musculus occipitofrontalis occipitalis originates at the linea nuchae suprema of the os occipitale and partly at the os temporale. Both muscle bellies send their fibers vertically in a cranial direction to radiate into the tendon plate of the skullcap. At this galea aponeurotica they find common ground. Each of the muscle bellies has an almost square plan. However, the venter frontalis becomes more pronounced and shows longer fiber tracts.

Like all skin muscles, the frontalis muscle in particular lies between the fascia and the skin . The venter frontalis is motor-innervated by the temporal rami of the facial nerve. In the venter occipitalis, the auricular nerve posterior to the facial nerve takes over the innervation.

Function & Tasks

Like all facial muscles, the occipitofrontalis muscle is also involved in human facial expressions. Facial expressions have expressive and communicative value for humans. Compared to verbal communication, mimic communication corresponds to a more original and relatively comprehensive form of understanding.

Even infants are able to interpret facial expressions. This connection confirms the deep genetic roots of mimic communication. Long before there was language, people were already able to express themselves thanks to mimic expression. In addition, facial expression is characterized by far fewer cultural differences than verbal expression. During verbal communication, people receive clues about the actual emotional state of their interlocutor through the smallest movements of facial expressions. Many mimic movements are almost automatic and thus ‘reveal’ what has been held back verbally.

Like every facial muscle, the musculus occipitofrontalis takes on communicative and expressive functions. Frontalis muscle contraction frowns and raises eyebrows. The muscle is thus involved in the facial expression of doubt or incomprehension. Contraction of the occipital muscle smooths the frown and lowers the eyebrows. The musculus occipitofrontalis summarizes two antagonistic muscles of facial expressions. While one of the muscle bellies is tensing, the other has to relax. Simultaneous contraction of both muscles is impossible.

Since the musculus occipitofrontalis releases individual fibers into other facial muscles, it is involved in further facial movements in the broadest sense. Due to the participation in the musculus procerus, individual fibers of the musculus occipitofrontalis are also not affected by the expression of anger in the form of a frown line. In addition, fibers of the muscle in the orbicularis oculi muscle are involved in the distribution of tear fluid . The musculus occipitofrontalis is called skin muscle because its contraction ultimately moves the skin of the forehead.

Diseases

Like all other muscles, the occipitofrontalis muscle forms a neuromuscular unit with its supplying nerve. This nerve corresponds to several parts of the facial nerve, which distributes contraction commands from the central nervous system in the form of bioelectrical excitation to the two individual muscles.Damage to the nerve can impair the work of the occipitofrontalis muscle and all other muscles of the facial muscles. Paralysis of the facial nerve can be preceded by congenital or acquired causes such as fractures of the skull . Inflammatory causes such as otitis media , chronic meningitis or Lyme disease are also conceivable causes. Apart from that, tumors of the cerebellopontine angle and immunological processes such as Guillain-Barré syndrome , Heerfordt syndrome or Melkersson-Rosenthal syndrome cause facial paralysis .

Mild facial paralysis shows only discrete symptoms. More severe paralysis entails changes in the entire facial expression, often with a disappearance or weakening of the frown, as well as incomplete eyelid closure and drooping corners of the mouth. Because the facial nerve sensitively innervates the tongue , taste disorders can also occur. Isolated paralysis of the occipital muscle has less of an impact on facial expressions than isolated paresis of the frontalis muscle.

Localized damage to the facial nerve, which can be caused primarily by inflammation, leads to isolated paralysis of a single muscle belly. Like any other muscle, the occipitofrontalis muscle can also be affected by typical muscle diseases such as myopathies or atrophy . Muscle fiber tears and related phenomena are extremely rare in facial muscles.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.