frontal sinuses



The frontal sinuses are one of the four pairs of
paranasal sinuses Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity. The maxillary sinuses are located under the eyes; the frontal sinuses are above the eyes; the ethmoidal sinuses are between the eyes and the spheno ...
that are situated behind the brow ridges.
Sinuses Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity. The maxillary sinuses are located under the eyes; the frontal sinuses are above the eyes; the ethmoidal sinuses are between the eyes and the sphenoi ...
mucosa A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It i ...
-lined airspaces within the bones of the face and skull. Each opens into the anterior part of the corresponding middle nasal meatus of the nose through the frontonasal duct which traverses the anterior part of the labyrinth of the
ethmoid The ethmoid bone (; from grc, ἡθμός, hēthmós, sieve) is an unpaired bone in the skull that separates the nasal cavity from the brain. It is located at the roof of the nose, between the two orbits. The cubical bone is lightweight due to a ...
. These structures then open into the semilunar hiatus in the
middle meatus In anatomy, the term nasal meatus can refer to any of the three meatuses (passages) through the skulls nasal cavity: the superior meatus (''meatus nasi superior''), middle meatus (''meatus nasi medius''), and inferior meatus (''meatus nasi inferio ...


Each frontal sinus is situated between the external and internal plates of the frontal bone.Frontal sinuses are rarely symmetrical. Their average measurements are as follows: height 28 mm, breadth 24 mm, depth 20 mm, creating a space of 6-7 ml.University of Texas Medical Branch

Blood supply

The mucous membrane of the frontal sinuses receives arterial supply via the supraorbital artery, and anterior ethmoidal artery.


The mucous membrane in this sinus is innervated by the supraorbital nerve, which contains the postganglionic
parasympathetic The parasympathetic nervous system (PSNS) is one of the three divisions of the autonomic nervous system, the others being the sympathetic nervous system and the enteric nervous system. The enteric nervous system is sometimes considered part of ...
nerve fibers for
mucous Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It is ...
secretion 440px Secretion is the movement of material from one point to another, such as a secreted chemical substance from a cell or gland. In contrast, excretion is the removal of certain substances or waste products from a cell or organism. The classica ...
from the
ophthalmic nerve The ophthalmic nerve (V1) is a sensory nerve of the face. It is one of three divisions of the trigeminal nerve (CN V). It has three branches that provide sensory innervation to the eye, the skin of the upper face, and the skin of the anterior scal ...

Anatomical variation

Frontal sinuses are rarely symmetrical as the
septum In biology, a septum (Latin for ''something that encloses''; plural septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interat ...
between them frequently deviates to either side of the midline. Rarely, one or both sinuses is hypoplastic or even absent.

Sexual dimorphism

Prominence of frontal sinuses is sexual dimorphic; they are more prominent in males, whereas less so in children and in females, resulting in an oblique forehead in males that is a male sexual characteristic.


The frontal sinuses are absent at birth, but are generally well developed, and functional between the sixth and eighth years, though they continue to grow slower until reaching their maximum size after
puberty Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a boy. ...
.Human Anatomy, Jacobs, Elsevier, 2008, page 210 This is why many children experience suddenly increased mucus production at this age and learn to react accordingly. The
frontal bone The frontal bone is a bone in the human skull. The bone consists of two portions.''Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, part ...
is membranous at birth and the sinus region is occupied by a developing recess until bodily development hastens and bones begin to ossify at age two. Consequently, this structure does not show on radiographs before that time. Sinus development begins in the womb, the maxillary and ethmoid sinuses are present at birth. Sphenoidal sinuses are present at birth as well but are very small. Approximately 5% of people have absent frontal sinuses.


Through its copious mucus production, the sinus is an essential part of the immune defense/air filtration carried out by the nose. Nasal and sinal mucosae are
ciliated The cilium, plural cilia (), is a membrane-bound organelle found on most types of eukaryotic cell, and certain microorganisms known as ciliates. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike projec ...
and move mucus to the
choanae The choanae (singular choana), posterior nasal apertures or internal nostrils are two openings found at the back of the nasal passage between the nasal cavity and the throat in tetrapods, including humans and other mammals (as well as crocodil ...
and finally to the stomach. The thick upper layers of nasal mucus trap bacteria and small particles in tissue abundantly provided with
immune cells White blood cells, also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from multi ...
antibodies An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
, and antibacterial proteins. The layers beneath are thinner and provide a substrate in which the cilia are able to beat and move the upper layer with its debris through the ostia toward the
choanae The choanae (singular choana), posterior nasal apertures or internal nostrils are two openings found at the back of the nasal passage between the nasal cavity and the throat in tetrapods, including humans and other mammals (as well as crocodil ...

Clinical significance

Infection of the frontal sinus causing sinusitis can give rise to serious complications, as it is in close proximity to the orbit and cranial cavity ( orbital cellulitis,
epidural Epidural administration (from Ancient Greek ἐπί, , upon" + ''dura mater'') is a method of medication administration in which a medicine is injected into the epidural space around the spinal cord. The epidural route is used by physicians an ...
and subdural abscess,
meningitis Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, headache, and neck stiffness. Other symptoms include confusion o ...
). Endonasal approach into the frontal sinus in children with acute and chronic frontal sinusitis without the usage of surgical optics is not successful, because in this case the operation is performed almost blindly and technically difficult even in adults.


Frontal sinus fractures occur from trauma to the part of the frontal bone that overlies the sinus, often from motor vehicle accidents and falls. The hallmarks of a frontal sinus fracture is a frontal depression in the anterior table of the bone. Additionally, clear fluid leaking from the nose may indicate that fractures to the posterior table have torn into the
dura mater In neuroanatomy, dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous system ...
, creating a
cerebrospinal fluid Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates. CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the ...
leak. Goals in management are to protect the intracranial structure, control any existing CSF leakage, prevent late complications, and aesthetically correct the deformity caused, if any. In anterior table fractures, if the table is minimally displaced, there will be no treatment necessary, only observation. If largely displaced, the correction is open reduction and internal fixation. If inhibiting the nasofrontal outflow tract, procedure is to undergo open reduction and internal fixation of the anterior table and osteoplastic flap with obliteration. In posterior table fractures, a nondiplaced fracture with no CSF leak will only be observed. Those with a CSF leak will undergo sinus exploration if the CSF leak is not internally resolved within 4 to 7 days. With more dramatic displacements, sinus exploration will be required to determine the required level of cranialization, obliteration, and reparation to the dura.

Aesthetic reconstruction

In the case of facial feminization surgery, modifications to the frontal sinus can be made to make the face more feminine, alongside softening the orbital rims. The forehead operations for feminization were first described by Dr. Douglas Ousterhout in the 1980s. Those operations consisted of four different techniques based on the anatomy of the patient. They were named arbitrarily by number (Type 1, Type 2, Type 3 and Type 4), with no particular relevance to their level of difficulty or frequency. * Type 1 The Type I forehead describes a forehead with an absent frontal sinus or alternatively with sufficiently thick bone overlaying the frontal sinus so that burring alone is enough to correct the forehead. This type of forehead tends to occur in approximately 3% to 5% of the population. In these situations, the operation consists of using rotary instruments to shape and contour the bone to the desired level, while observing the thickness of the bone to avoid penetrating the intracranial space. The main risks associated with this operation tend to be bleeding. There are often venous lakes present throughout the frontal bone. * Type 2 The Type II forehead describes another uncommon situation. This describes a patient with brow bossing; however, the bossing is at the correction position in terms of prominence. Therefore, the problem lies primarily above the bossing. We see this forehead type at about the same frequency as we see the Type I forehead. The Type II forehead is corrected by using a filling material such as methyl methacrylate.7 Other materials may be more ideal at this point; however, none are superior in terms of cost to methyl methacrylate. Although many surgeons do not consider the cost of the materials they are using, hydroxyapatite and calcium phos-phate bone cements cost approximately 1000 times that of methyl methacrylate. The advantage of bone cement is its adherence to the underlying bone, and the more analogous nature to native bone substrate. The material is applied to fill in the area above the bossing, and then gently contoured to blend with the transverse forehead bossing thereby-creating a uniformly round forehead * Type 3 The Type III forehead is the most common situation and occurs in more than 90% of patients. The forehead, in this situation, has a prominent bossing across the top of the brows, and that bossing is overly projected. A frontal sinus is present. The thinness of the sinus precludes using exclusively rotary instruments to thin the bone. An osteotomy and reconstruction are the only operations to provide the proper round shape to the forehead with the decreased prominence that is necessary for a soft forehead, which involves a setback of the anterior table of the frontal sinus. This procedure is described as Type 3 Forehead Cranioplasty. * Type 4 This operation can be described as an extended Type II operation. In this situation, the entire forehead is diminutive, including the area underlying the brows, and the entire forehead requires augmentation. Regardless of the material type, care should be taken to avoid having the implant sit directly underneath the incision as this leads to a higher rate of infection and removal. Treatment of the orbital rim is almost always necessary in all these various forehead operations, regardless of what is done with the frontal bossing. Deschamps-Braly JC. Approach to Feminization Surgery and Facial Masculinization Surgery: Aesthetic Goals and Principles of Management. ''J Craniofac Surg''. 2019;30(5):1352‐1358. doi:10.1097/SCS.0000000000005391


External links

* * (, )
Use of Frontal Sinus Transillumination For Cranioplasty in Facial Feminization Surgery

Approach to Feminization Surgery and Facial Masculinization Surgery: Aesthetic Goals and Principles of Management.
{{Authority control Bones of the head and neck Otorhinolaryngology