Sinonasal Papilloma Images

To understand the frontal recess, you need first of all to know the different relationships of the uncinate process and then the variation in pneumatization of the air cells that extend into it.

Access to the frontal recess may be altered by the attachment of the uncinate process. If the uncinate process is attached to the lamina papyracea, the agger nasi air cells, or the lateral wall, it will not get in the way of the frontal recess (type A, where the uncinate process attaches to the lateral nasal wall so the frontal sinus drains into the middle meatus) (Fig. 5.44a-d). The "dead end" between the uncinate process and the lateral nasal wall is called the "terminal recess" (Fig.5.45a, b). If the posterior edge of the uncinate process is followed superiorly, this will lead to the re-cessus terminalis, a blind ended alley between the un-cinate process and the lateral wall of the nose.

Alternatively, the uncinate process can attach to the skull base or middle turbinate and limit anterior access as it forms a web that gets in the way of an anterior approach. In type B1, the uncinate process attaches to the skull base (Fig. 5.46a, b). In type B2, the uncinate process attaches to the middle turbinate (Fig. 5.47a, b). In these patients the frontal sinus drains directly into the ethmoid infundibulum (Fig. 5.48a, b).

The variability of the anterior ethmoid air cells makes them a fascinating subject on their own (Fig. 5.49a, b-5.57a, b). In over 94% of people there

Imaging Inverted Nasal Papilloma
Fig. 5.44 a, b Coronal CT scans showing a type A insertion of different appearances on sequential coronal CT cuts of a type A the uncinate process to the lateral nasal wall. Find it by follow- uncinate process. ing its posterior free edge. c, d Line diagrams to show the
Supraorbital Meatal Line

Fig. 5.45 a, b In a the blue wire extends into a bulla frontalis. In b the terminal recess is revealed by a green wire when the uncinate process is folded back.

Fig. 5.45 a, b In a the blue wire extends into a bulla frontalis. In b the terminal recess is revealed by a green wire when the uncinate process is folded back.

Uncinate Process Middle Turbinate

Fig. 5.46a, b In type B1 the uncinate process attaches to the skull base.

Fig. 5.46a, b In type B1 the uncinate process attaches to the skull base.

are anterior ethmoid air cells over the lacrimal bone or adjacent to the anterior aspect of the middle turbi-nate; these are called agger nasi air cells. A high anterior ethmoidal cell that has pneumatized into the frontal bone is called the bulla frontalis and this can displace the frontal recess posteriorly (Fig. 5.50a, b).

The bulla frontalis can be so large that it can mimic the frontal sinus, almost forming a sinus within a sinus (Fig. 5.51a, b).

Not infrequently a supraorbital cell, a posterior cell in the anterior ethmoid complex that is well pneuma-tized, can extend laterally into the frontal bone over b a a b

Agenesis Frontal Sinuses
Fig. 5.48a, b In these specimens the frontal sinus can be seen directly draining into the ethmoid infundibulum (green wire)— type B1.
Ethmoid Sinus Papilloma
Fig. 5.49a, b In these specimens the uncinate process is curl- resected in b to allow the frontal sinus to be seen to drain ing medially (*) to join the middle turbinate, which has been directly into the ethmoid infundibulum (green wire)—type B2.
Agger Nasi Coronal

Fig. 5.51 a Coronal, axial, and sagittal scans taken during computer-aided surgery, showing a pneumatized bulla frontalis extending into the frontal sinus, which helps to distinguish it in this

Fig. 5.50a, b Coronal CT scans showing the lower agger nasi air cells (1), with the bulla frontalis (2) extending above them into the frontal sinus.

Fig. 5.50a, b Coronal CT scans showing the lower agger nasi air cells (1), with the bulla frontalis (2) extending above them into the frontal sinus.

Bulla Frontalis

Fig. 5.51 a Coronal, axial, and sagittal scans taken during computer-aided surgery, showing a pneumatized bulla frontalis extending into the frontal sinus, which helps to distinguish it in this

Fig. 5.51 b The blue wire is in a bulla frontalis and the red wire is in the frontal recess and sinus.

the orbit and also narrow the frontal recess by pushing it forward (Figs. 5.52a, b, 5.53a, b, 5.54a-c). Occasionally air cells exist within the frontal sinus itself, with the ostia of these cells draining within the frontal sinus (Fig. 5.55). Another variation is the intersinus septal cell that may extend into the crista galli; this cell often drains into the frontal recess area (Fig.5.56a, b).

To explain the variations that can occur, you need to imagine different shapes and sizes of party balloons that are blown up to encroach on or extend through the channel of the frontal recess. Imagine the pneumatized ethmoid cells, agger nasi, bulla frontalis, or a supraorbital cell as balloons that can expand to narrow access to the frontal recess that forms a medial crevice between these and the middle turbinate (Fig. 5.57a, b).

Middle Turbinate Anatomy

Fig. 5.52a, b A large supraorbital extension (arrow) just behind the opening of the frontal recess ( ). The frontal recess is very narrow and is positioned anteriorly because of the large supraorbital cell.

Fig. 5.52a, b A large supraorbital extension (arrow) just behind the opening of the frontal recess ( ). The frontal recess is b very narrow and is positioned anteriorly because of the large supraorbital cell.

Red Turbinates
Fig. 5.53 a The red and blue wires both enter the right frontal sinus; the white wire goes into a supraorbital cell. b A view from above shows the red and blue wires entering the frontal sinus;

note that the roof of this area has been removed so they can be seen.

Middle Turbinate

Fig. 5.55 A coronal CT scan showing bilateral bulla frontalis > (1) and an intersinus septal cell (2) in between.

Sinusitis FrontalisEthmoid Bilateral Endoscopy
Fig. 5.56a, b Coronal CT scans showing an intersinus septal cell that is draining to the left.
Septum Nasi Bony Part Coronal
Fig. 5.57 a Coronal CT scan showing agenesis of the frontal sinus. b Minimal pneumatization on the left into the frontal/ethmoid bone.
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Responses

  • RAZANUR
    What is agger nasi cell pneumatization type 1?
    7 years ago
  • jenson
    How do the frontal sinuses drain?
    6 years ago

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