Coronal CT scans demonstrate the superior attachment of the uncinate process, which determines whether the inferior compartment of the FSDP is formed by the ethmoid infundibulum or the middle meatus Figs 4E and 5. Display of the FSDP is useful when evaluating the cause and potential surgical therapy for obstruction of the frontal sinus 4.
Frontal Sinus - National Library of Medicine - PubMed Health
The nomenclature used to describe these cells varies with their position. Ethmoid air cells that encroach upon the anterior aspect of the superior compartment of the FSDP or upon the frontal sinus itself are designated frontal air cells. A classification of frontal cells is given by Bent et al 8 ; however, further work is needed to understand the complex anatomy and variations of the frontal sinuses and FSDPs. A, Composite image displaying the drainage pathways of the frontal, ethmoid, and sphenoid sinuses in relation to a sagittal CT section through the skull illustrated in Figs 3 and 4.
The frontal ostium forms the upper border of the superior compartment of the FSDP. The superior compartment of the FSDP drains posteroinferiorly into a narrow inferior compartment situated always anterior to the ethmoid bulla.
The inferior compartment of the FSDP is formed by the ethmoid infundibulum when the superior portion of the uncinate process attaches to the skull base but is formed instead by the middle meatus when the uncinate process attaches to the lamina papyracea. The basal lamella of the middle turbinate colored green divides the ethmoid air cells into anterior and posterior groups. The agger nasi air cell is classified as an extramural ethmoid air cell, because it projects anterior to the ethmoid bone.
This cell frequently extends to the lacrimal bone and the frontal process of the maxilla. B, Summary of the typical drainage pathways of the paranasal sinuses, including the drainage pathway of the maxillary sinus.
Ultimately, all sinus drainage is directed toward the nasopharynx. The superior compartment of the FSDP.
Shown are oblique A and straight B views of the superior and inferior surfaces of the frontal and ethmoid bones of two different specimens. The paired air spaces situated beneath the frontal sinuses and the frontal ostia at the anteroinferior aspect of the frontal bone drain red arrows into the paired labyrinthine air spaces at the anterosuperior aspect of the ethmoid bone.
In the intact skull of a single specimen, these spaces would join smoothly to form the paired superior compartments of the FSDPs. Common anatomic variations affecting the superior compartment of the FSDP include osseous septations Fig 6 and marginating air cells Fig 7. These anatomic variations cause substantial variation in the size and shape of the superior compartments. Nonetheless, the superior compartments ultimately drain into the middle meatus, either directly or via the ethmoid infundibulum Fig 5.
The nasal septum is a composite structure, formed by the perpendicular plate of the ethmoid bone anterosuperiorly and by the vomer posteroinferiorly. The inferior margin of the vomer rests upon the nasal crest of the maxillary and palatine bones.
The superior margin of the vomer supports the perpendicular plate of the ethmoid bone. Removal of the nasal septum reveals the inferior, middle, and superior turbinates.
The superior turbinate attaches to the skull base. Its superior border has variable shape. Image C displays a simplified posteromedial oblique view of the middle turbinate and its basal lamella. The basal lamella has three portions. The vertical portion of the basal lamella attaches to the cribriform plate, the middle and posterior portions attach to the lamella papyracea, and the posterior margin of the basal lamella attaches to the perpendicular plate of the palatine bone.
Typically, the vertical, middle, and posterior portions of the basal lamella are oriented in near-sagittal, coronal, and horizontal planes, respectively. Usually, the middle and posterior portions appear irregular in shape because of encroachment by adjacent ethmoid air cells. D, Removing the middle turbinate and the vertical portion of the basal lamella exposes, from anterior to posterior, the agger nasi extending to the frontal process of the maxillary bone, the lacrimal bone, the uncinate process of the ethmoid bone extending upward toward the skull base, the hiatus semilunaris dashed red line , the ethmoid bulla, and the middle and posterior portions of the basal lamella extending laterally toward the lamina papyracea.
The hiatus semilunaris is the narrow, slitlike passage between the uncinate process and the ethmoid bulla, through which the ethmoid infundibulum communicates with the middle meatus 6. The ethmoid infundibulum is the space bounded by the uncinate process anteromedially, the ethmoid bulla posterolaterally, and the lamina papyracea anterolaterally 6. Simultaneous removal of the wall of the frontal sinus shows the relationship of the frontal ostium to the superior compartment of the FSDP and how the sinus cavity tapers inferiorly toward the frontal ostium.
Removal of the anterior portion of the uncinate process exposes the ethmoid infundibulum. In this specimen, the superior compartment of the FSDP drains directly into the ethmoid infundibulum, which then drains through the hiatus semilunaris to the middle meatus. The frontal ostium extends posteriorly from the anterior frontal bone ridge to the posterior wall of the frontal sinus and is oriented nearly perpendicular to the posterior wall of the sinus. The superior compartment of the FSDP lies inferior to the frontal ostium.
In this specimen, the inferior compartment of the FSDP is the ethmoid infundibulum. The middle and posterior portions of the basal lamella of the middle turbinate green separate the anterior and posterior ethmoid air cells see also Fig 4 E, the coronal CT of the same specimen.
A, Frontal oblique view of the same skull specimen illustrated in Fig 3. Resection of the anteroinferior portion of the middle turbinate green exposes the curved uncinate process red just superior to the inferior turbinate. In this specimen, the anterior portion of the uncinate process extends to the skull base. B and C, Sagittal CT sections color coded to display the uncinate process red and the middle turbinate including the basal lamella green.
Note that the different portions of the basal lamella are oriented more nearly vertical, or horizontal, facilitating their identification on sagittal and coronal CT sections. D — H, Sequential coronal CT sections, displayed from anterior to posterior to illustrate the changing relationships and attachments of the color-coded structures. The frontal ostium is more easily identified in the sagittal plane B than in the anterior coronal plane D , where the border between frontal sinus and FSDP is difficult to define.
E, The anterior portion of the uncinate process red extends upward to the skull base in the right side of this specimen, so the FSDP includes the ethmoid infundibulum. National Center for Biotechnology Information , U.
What is a systematic review? Finding systematic reviews Understanding research results Blog. Frontal Sinus A type of paranasal sinus a hollow space in the bones around the nose. Click to enlarge The nose and sinuses around the nose National Institutes of Health. Terms to know Ethmoid Sinus A type of paranasal sinus a hollow space in the bones around the nose.
Acute Frontal Sinusitis Surgery
Ethmoid sinuses are found in the spongy ethmoid bone in the upper part of the nose between the eyes. They are lined with cells that make mucus to keep the nose from drying out. Maxillary Sinus A type of paranasal sinus a hollow space in the bones around the nose. There are two large maxillary sinuses, one in each of the maxillary bones, which are in the cheek area next to the nose. The maxillary sinuses are lined with cells that make mucus to keep the nose from drying out. Nasal Cavity The space inside the nose. Cribriform plate Crista galli Olfactory foramina Perpendicular plate.
Lateral surface Orbital lamina Uncinate process Medial surface Supreme nasal concha Superior nasal concha Superior meatus Middle nasal concha Middle meatus. Ethmoid sinus ethmoidal foramina Posterior Anterior. Anatomy of the human nose. Ala of nose nasal cartilages of the septum Greater alar Lesser alar Lateral nasal Accessory nasal Vomeronasal.
Nasal vestibule Nostril Posterior nasal apertures. Supreme nasal concha Superior nasal concha Middle nasal concha Inferior nasal concha Nasal meatus: Supreme superior middle inferior Sphenoethmoidal recess Ethmoid bulla Agger nasi Ethmoidal infundibulum Semilunar hiatus Maxillary hiatus. Nasal septum Vomeronasal organ. Maxillary sinus Sphenoidal sinuses Frontal sinus Ethmoid sinus.
Outline of bones of face, showing position of air sinuses. Nose and nasal cavities. Anatomical terminology [ edit on Wikidata ].
Related The Frontal Sinus
Copyright 2019 - All Right Reserved