The lateral wall of the nasal cavity is formed by several bones including the nasal, maxilla, lacrimal, ethmoid, palatine and sphenoid bones. It contains three bony projections called turbinates. Several anatomical structures are located within the lateral wall including the agger nasi cell, ethmoid bulla, uncinate process and ostiomeatal complex. The document describes the bones, turbinates, sinuses and various anatomical variations that can be present within the lateral wall of the nasal cavity.

1. ANATOMY-LATERAL WALL OF
NASAL CAVITY

2.  Bones: The lateral wall is formed
by following bones:
– Nasal bone
– Maxilla:
Frontal process
and medial surface
maxilla
and medial wall
of maxillary sinus

3. – Lacrimal bone
– Inferior turbinate
– Ethmoid: Lateral
mass of ethmoidal bone
– Palatine bone:
Perpendicular plate
– Sphenoid: Medial
pterygoid plate

5.  Anteriorly in the area of the nostril, lined by
skin and has hair -> vestibule.
 Behind this structure less -> the atrium

6.  Bulge anterior to the middle turbinate is
the agger nasi cell (most anterior
ethmoidal cell)

7.  It is the most anterior part of the ethmoid.
 It is represented by a small crest or mound on
the lateral wall just anterior to the attachment
of the middle turbinate.
 It may be pneumatized.

9. Lateral wall is marked by three bony
projections called turbinates or conchae-
superior (part of ethmoid),
middle (part of ethmoid),
inferior (separate bone).
sometimes a fourth turbinate concha suprema
may also be present.
 Below and lateral to each turbinate is a
corresponding meatus.

10.  Inferior meatus- nasolacrimal duct opens in its
anterior part.
 Middle meatus- consists of bulla ethmoidalis,
hiatus semilunaris, infundibulum.
 Frontal, maxillary and anterior ethmoidal
sinuses open into middle meatus.
 Superior meatus- posterior ethmoidal sinuses
open into it.
 Sphenoethmoidal recess- triangular fossa
above the superior meatus. Sphenoidal sinus
opens into it.

11. •The inferior turbinate is fairly straight and
structure less as compared to the middle
turbinate, which is convoluted showing many
features and anatomical variations.
•

12. The posterior end of the middle turbinate ends
at the level of the roof of the posterior
choana.
The eustachian tube lies in the nasopharynx at
the level of the inferior turbinate 1 cm behind
its posterior attachment.
The fossa of Rosenmuller forms a deep cleft
behind the torus tubaris.

13.  convoluted structure bending similar to a
dried leaf.
 It can be divided into three parts.
1. The anterior one-third is in the sagittal plane
and is attached to the cribriform plate at the
junction of the medial and lateral lamellae. It
also takes a small anterior attachment to the
frontonasal process of the maxilla.

14. 2. The middle one-third lies in the coronal plane
and is attached to the lamina papyracea. It
separates the anterior ethmoidal cells from
the posterior ethmoidal cells. Since it
stabilizes the middle turbinate, it is called the
ground lamella or the basal lamella.
3. The posterior third lies in the horizontal
plane and is attached to the lamina papyracea
and the perpendicular plate of the palatine
bone extending upto the roof of the posterior
choana.

18.  Concha bullosa is a
variation originated from
pneumatization of the
bone plate by extension of
ethmoid sinus cells.
 May be uni- or bilateral.
 Varied degrees of
pneumatization of the
concha may be observed,
possibly causing middle
meatus or infundibulum
obstruction.

19.  The middle turbinate
may show a sharp
bend laterally instead
of its usual smooth
medial curvature.
 This is the
paradoxically bent
middle turbinate.
 It is quite often
bilateral and can block
the infundibulum

20. Interlamellar cell of
Grunwald
 The superior meatus
may pneumatize the
vertical lamella ofthe
middle turbinate to
produce what is called
the interlamellar cell of
Grunwald

21.  Turbinate sinus
 A normally curved
middle turbinate may
curl upon itself to
produce a concavity
within it.This
concavity is called the
turbinate sinus

22.  It is superior extension of the ethmoid.
Anteriorly it fuses with the postero medial
wall of agger nasi cell and postero medial wall
of nasolacrimal duct.
 It has free superio-posterior edge.
 floor and medial wall of infundibulum is
formed by the uncinate process.
 It is approximately 3 to 4 mm wide and 1.5 to
2 cm in length.

25.  Variations in the superior insertion of the
uncinate process

26.  A:Type 1 (insertion into the lamina
papyracea).
 B:Type 2 (insertion into the posterior wall of
agger nasi cell).
 C:Type 3 (insertion into the lamina
papyracea and junction of the middle
turbinate with the cribriform plate).
 D:Type 4 (insertion in to junction of the
middle turbinate with the cribriform plate).
 E:Type 5 (insertion into the skull base).
 F:Type 6 (insertion into the middle turbinate)

27.  It is the largest anterior ethmoidal cell .
• Occasionally the bulla does not
extend upto the base of the skull and is
separated from it by the suprabullar
recess.The retrobullar and suprabullar recesses
together form a semilunar space above and
behind the bulla called the sinus lateralis of
Grunwald.

28.  medial: middle turbinate;
 lateral: lamina papyracea;
 superior: roof of ethmoid;
 inferior and anterior: unicate process;
 posterior: basal Lamella of the middle
turbinate.

29. Sometimes a cleft is encountered between the
posterior wall of the bulla and the basal lamella
of the middle turbinate, the retrobullar recess.
The space between it and the ethmoidal roof is
called the suprabullar recess.

30.  The inferior hiatus semilunaris: Lying between
the free posterior margin of the uncinate process
and the anterior surface of the ethmoidal bulla.
 Sickle-shaped two-dimensional space.& three-
dimensionalspace called the infundibulum.
 The superior hiatus semilunaris :This cleft
between the ethmoidal bulla and the middle
nasal meatus exists, when there is a marked
recess posterior to the ethmoidal bulla

31. The hiatus semilunaris inferioris leads into the
infundibulum
The hiatus semilunaris superioris leads into the
sinus lateralis of Grunwald.
Boundaries:-
 Roof - formed by the ethmoid fovea
 Floor-by the ethmoidal bulla
 Posteriorly - by the ground lamella of the
 middle turbinate
 Anteriorly- it opens into the frontal recess. Laterally-
lamina papyracea
 Medially is the middle turbinate.

33.  The middle meatus is the space below and
lateral to the middle turbinate, and is often
functionally referred to as the ostiomeatal
complex.
The uncinate process, the bulla and the
intervening infundibulum form
the key area or the ostiomeatal unit into
which anterior ethmoids, the maxillary and
the frontal sinuses drains.

36.  Found in the most antero superior part of the
middle meatus.
Boundaries:-
anteriorly : the agger nasi cell
posterior wall : by the bulla ethmoidalis.
medial: middle turbinate
lateral: lamina papyracea, lacrimal bone;
superior: skull base;
inferior: dependent upon the attachment of the
uncinate process;

39.  frontal infundibulum, frontal ostium and the
frontal recess together form the “hour-glass
configuration”

40. Most commonly (80 %) it attaches to the
lamina papyracea in the form of a dome.
This upper dome shaped attachment of the
uncinate process within the frontal recess has
been graphically described by Stammberger as
an eggshell in an inverted egg-cup.
 The recess, which is enclosed within this
dome,is called the Recessus terminalis

42.  The anterior and posterior ethmoid air cells may
pneumatize surrounding :-
lacrimal bone -> AGGER NASI CELLS
frontal bone -> FRONTAL CELLS
above sphenoid -> ONODI CELLS
roof of maxillary sinus -> HALLER CELLS
middle turbinate -> CONCHA BULLOSA

44. Infraorbital ethmoid cells or Haller cells are
ethmoid air cells located anteriorly to the
ethmoid bulla, along the orbital floor, adjacent
to the natural ostium of the
maxillary sinus, which
may cause mucociliary
drainage obstruction,
predisposing to the
development of sinusitis.

45.  :This is formed by lateral and posterior
pneumatization of the most posterior
ethmoid cells over the sphenoid sinus.
 The presence of Onodi cells increases the
chance that the optic nerve and / or carotid
artery would be exposed in the pneumatized
cell.

47.  BENT AND KUHN CLASSIFICATION OF
FRONTAL CELLS :-
 The anterior ethmoidal cells may migrate
anterosuperiorly into the frontal recess to
produce different types of frontal cells

53. It is bounded by:
 inferior: the maxillary process of the inferior
turbinate bone;
 posterior: the perpendicular plate of the
palatine bone;
 anterosuperior: a small portion of the
lacrimal bone;
 superior: the uncinate process and bulla of
the ethmoid.

54.  The normal ostium of the maxillary sinus is
 usually ovoid and tunnel like, having three-
dimensions.
 Accessory ostium is easily seen, usually
circular and has only two dimensions

57.  The frontal recess, the maxillary sinus and the
opening of the bulla into the middle meatus
are visualized

58.  The bulla may drain into the middle meatus,
the hiatus semilunaris inferioris or into the
sinus lateralis when present.
 The frontal sinus drains into the frontal recess
either medial or lateral to the uncinate
process depending on the mode of
attachment of the uncinate process. It may
also drain into the suprabullar recess when it
is present.

59.  The maxillary sinus shows no variation in
drainage and always drains into the
infundibulum.

60. It is a cleft-like, three dimensional space in the
lateral wall of the nose that belongs to the
anterior ethmoid.
Boundaries:
Medially: Uncinate process
Laterally: Lamina papyracea of the orbit
Posteriorly: Anterior surface of ethmoidal bulla

62.  The superior turbinate is always present and
acts as a guide for the sphenoid ostium.
 Pneumatized or paradoxically curved
 A fourth turbinate, i.e. the supreme
turbinate, which represents persistence of an
ethmoturbinal may be seen in the adult.

64.  The sphenoid sinus ostium lies high on its
anterior wall close to its roof.
 The anterior wall of the sphenoid sinus is thinner
superiorly and thicker inferiorly where it forms
the roof of the posterior choana.
 The sphenoid ostium lies 1-1.5 cm above the
roof of the posterior choana and approximately
2-3 mm away from the eptum.

66.  Superiorly is the bulge of the optic nerve,
 Posteriorly & inferiorly is the internal carotid
artery.
 The maxillarynerve inferolaterally
 the vidian nerve inferomedially.

68.  The olfactory fossa is formed by the horizontal
lamella of the cribriform plate, its vertical
lamellae and a part of the orbital plate of the
frontal bone.
 The thickness of the orbital plate of the frontal
bone is 0.5 mm.
 The vertical lamella in its thinnest part (where
the anterior ethmoidal artery perforates it) is
only 1/10th this thickness, i.e. 0.05 mm

69.  The cribriform plate may present at variable
levels and, it is classified according to the
criteria developed by Keros.
 It is based on the height of the olfactory
fossa in relation to the roof of the ethmoid
sinus as compared with the length of the
lateral lamella of cribriform plate

70.  The depth of the olfactory fossa varies and
has been classified by Keros into
 •Type I: 1-3 mm •
 Type II: 4-7 mm •
 Type III: 8-17 mm

72. Relation b/w posterior group of sinuses with
optic nerve.

75.  Coronal CT
shows type III
optic nerve
(arrows)
where more
than 50% of
the nerve is
surrounded
by air

79.  Drains with the external nose to the
submandibular nodes anteriorly
and to the lateral pharyngeal, retropharyngeal
and upper deep cervical nodes posteriorly.

80. Apart from the olfactory supply on the superior
concha,
the lateral wall receives ordinary sensation
from the anterior ethmoidal nerve
anterosuperiorly and from
branches of the pterygopalatine ganglion and
anterior palatine nerves posteriorly

86. ThankYou