Frontal Bone: Structure, Function & Diseases

The frontal bone (lat. Os frontale ) is one of the human skull bones. Due to its frontal position, it is distinctive for the appearance of the human face and also fulfills anatomically Vielfälitge important functions.

What is the frontal bone

The frontal bone sits in the upper frontal part of the human skull and thus partially surrounds the brain. Likewise, it partially functions as the bone base for the human face. Its scientific name, Os frontale, is derived from the Latin terms os (bone) as well as frons (forehead). The Os frontale is involved in the formation of the anterior cranial fossa as well as the orbital roof and is usually present in unpaired form in adult humans after fusion of the cranial bones in the area of the fontanelles. The frontal sinuses, as part of the paranasal sinuses, are also contained within the frontal bone.

Anatomy and structure

The frontal bone is roughly divided anatomically into three parts: The squama frontalis, also called the frontal bone scale, the pars orbitalis, and the pars nasalis.

  • The squama frontalis, which in turn is divided into the facies externa as well as the facies interna, is vertically arranged in correspondence to the human forehead. The Facies externa is the outer surface, the Facies interna refers to the surface of the Squama frontalis lying on the inside of the skull.

Characteristic of the human skull as well as that of primates are also the so-called eyebrow ridges (Arcus superciliares) lying on the Facies externa. These are typically more pronounced in males than in females.

  • The pars orbitalis forms the horizontally applied part of the frontal bone and consists of two triangular-shaped, thin bone plates, the orbital plates. Both orbital plates are pierced by a longitudinal suture. This part of the bone forms the roof of the human eye sockets as well as nasal cavity.
  • The pars nasalis forms the smallest section of the frontal bone and also the connection between the two partes orbitales. From it protrudes the spina nasalis, which together with the maxilla (maxilla) as well as the nasal bone (os nasale) forms the nasal root. The nasal cavity is bounded by the bony part of the pars nasalis.

Function and tasks

The human skull serves primarily to protect the delicate brain, as well as to form the bone foundation for the human face. Accordingly, this is also divided into the cerebral skull (neurocranium) as well as the facial skull (viscerocranium). A special feature of the frontal bone is that the squama frontalis, as part of the anterior skull axis, is included in the cranium, while the pars orbitalis and pars nasalis are included in the definition of the facial skull. Accordingly, the functions of the frontal bone are assigned to both areas of responsibility. On the one hand, the squama frontalis covers the human brain on the frontal side of the head and thus protects it from external force and associated injuries to the sensitive organ. Likewise, this part of the frontal bone contains the frontal sinus, one of the sinuses. This is a paired cavity located within the bone. The frontal sinus is completely lined with mucosa and filled with air. Its primary function is to heat the air breathed and to resonate nasal sounds. Likewise, its function as a pneumatisationsraum (air-filled cavity in the bone) is an extension of the mucosal surface and thus defense against infection. This pneumatization space in the frontal bone also saves weight on the frontal bone similar to other cranial bones. The pars orbitalis is counted as part of the orbits to the facial skull. The orbits form a pit on the skull of about 4-5 centimeters deep, in which the human eye as well as its accessory organs are embedded. They serve as a bony protection of the sensitive organs of vision. Likewise, the openings inside allow the passage of nerves, blood vessels and lacrimal duct. The pars nasalis is associated with the roof of the nasal cavity, which in turn is part of the upper respiratory tract. This interior space of the nose is connected to the outside world through the nostrils, allowing the supply of vital breathable air.

Diseases and ailments

Pain in the frontal bone can indicate a variety of ailments.Very often, this is an overuse headache due to too much stress and a lack of time for physical as well as mental rest. However, the symptoms can usually be easily counteracted by short relaxation sessions in everyday life. Similarly, headaches in the forehead area are also often among the main complaints in patients of migraine and cluster headache. The exact causes of the latter two diseases are still unclear, but in most cases so-called “triggers” can be identified, i.e. triggers for the recurring headache attacks. These vary greatly from person to person, but can be specifically avoided once they have been identified. Eye problems can also be the cause of said pain. Impaired vision or other eye diseases are a frequent trigger of headaches in the forehead and eye area and can go unnoticed by sufferers without clarification by a specialist. Furthermore, in the context of colds, there is always the risk of sinusitis, an inflammatory change in the mucous membrane of the paranasal sinuses caused by bacteria or viruses. The frontal sinus, as part of the paranasal sinuses, can be affected by this disease and cause the patient probing pain accompanied by a feeling of pressure. Sinusitis can be acute or chronic and requires different treatment methods depending on its severity. These can range from the simple administration of herbal medicines to the need for surgery. If pain occurs in the above-mentioned area after external violence such as a bump or blow, this may indicate a skull or craniocerebral trauma. The severity can also vary greatly in this case. Depending on the type and duration of the pain, as well as any additional symptoms that may occur, such as nausea or impaired consciousness, this can range from injuries that do not require further treatment to those that are life-threatening. Seeking medical advice after head injuries is generally recommended.