surgical anatomy of nose is a humble attempt to make the anatomy of nose simpler and easy for medical students and fellow physicians. at the end of the presentation the students will be able to identify all the structures.

1. Surgical anatomy of
nose
DR. PRATHYUSHA PG ENT
NARAYANA MEDICAL COLLEGE
NELLORE

2.  Introduction
 embryology
 External anatomy
 Nasal septum
 Lateral wall of nose
 Applied anatomy

3. DEVELOPMENT OF NOSE
 The developmental precursors of the nose are the
neural crest cells,
 which commence their caudal migration toward
the midface around the fourth week of gestation.

4. Five facial prominences
 1. FRONTONASAL prominence
 2. MAXILLARY prominence
 3. MEDIAL NASAL prominence
 4. LATERAL NASAL prominence
 5. MANDIBULAR prominence

6.  Appearance of nasal placodes at the end of 4th week
of IUL
 NASAL PITS are formed on 5th week of IUL, by
invagination of nasal placodes.
 Nasal prominence are formed following the formation
of Basal pits

8.  NASAL PROMINENCE divided into 2 subdivisions:
 1. LATERAL nasal prominence
 2. MEDIAL nasal prominence

9. Medial nasal process
 Philtrum
 Medial crus of lower lateral cartilage

10. Lateral nasal process
 Upper nasal bones
 Upper nasal lateral cartilages
 Lateral crus of lower lateral cartilages

11. Nasal Septum Development
 embryo stage (6th week)
 Fusion of maxillary to frontonasal process.
 Midline ridge from posterior end of frontonasal process
forms septum

16. Development of lateral wall of
nose
 During 8th week of IUL 6 to 7 ridges appear on the
lateral nasal wall,
 those ridges are called as ETHMO TURBINALS.

17.  ETHMO TURBINAL
 1. ASCENDING portion forms AGGER NASI
 2. DESCENDING portion forms UNCINATE
PROCESS
 2nd ETHAMO TURBINAL forms MIDDLE
TURBINATE.
 3rd ETHAMO TURBINAL forms SUPERIOR
TURBINATE
 4th and 5th ETHAMO TURBINAL forms SUPREME
TURBINATE
 MAXILLO TURBINAL forms INFERIOR TURBINATE

18.  FURROWS between each ETHAMO TURBINALS
forms respective NASAL MEATUSES
 1st FURROW :- MIDDLE MEATUS (b/w 1st & 2nd ET)
 2nd FURROW :- SUPERIOR MEATUS
 3rd FURROW :- SUPREME MEATUS
 4th FURROW :- INFERIOR MEATUS

21. External nose
 Upper portion
1. nasal bones
2. perpendicular plate of ethmoid
3. frontal process of the maxillary bone

22.  Middle portion:
1. upper lateral cartilages
2. dorsal portion of quadrangular cartilage

23.  Lower portion
1. bilobed alar cartilages (nasal tip
detereminant)
2. accessory cartilages
3. fibrofatty tissue

25. External anatomy

26. Integrity of the external nose
 Keystone area
area overlapped by nasal bones over upper
lateral cartilages
 Junction of septal cartilage, perpendicular plate
of ethmoid, and nasal bone
 Critical in the support of the nasal dorsum.

27.  Aponeurotic attachment of upper lateral
cartilages to frontal process of the maxilla
 Interdomal ligament the lower alar cartilages
make it a single unit

28. Keystone area Fibrous tissue

29. Nasal bone
 Note it is thicker superiorly
and tapers inferiorly

30. Key points on external nose
 Nasal bone is thick superiorly and thin below
intercanthal line (fracture vulnerability)
 Pole and tent relationship between ethmoid and
the nasal bones makes ethmoid bone fracture
vulnerable

31.  Nasal cartilages absorb significant amount of force.
 Avulsion and dislocation of upper lateral cartilages give
“ hollowed out” appearance
 External nasal artery a terminal branch of ophthalmic artery
exits between nasal bone and upper lateral cartilage is prone
for injury

32. nasal septum

33.  Columellar septum : formed by medial crura of alar cartilages
 Membranous septum : devoid of bone or cartilaginous support
 Septum proper

36. Ethmoid bone
 Needs to be understood in a proper way
 Forms most of the skeletal framework of the nose

37. Ethmoid bone
 Single delicate bone with horizontal cribriform
plate and vertical perpendicular plate of ethmoid
 Cribriform plate fits into notch of the frontal bone
 It transmits olfactory nerves as well as anterior and
posterior ethmoidal arteries
 Crista galli is a projection on cribriform plate

41. Inferior turbinate Septal view
orange is lacrimal process blue ethmoidal process

42. Inferior turbinate meatal view
green is maxillary process

43. Vomer bone

44. Blood supply of nasal
septum

46. Woodruffs plexus

47.  anterior and posterior ethmoidal arteries are
branches of ophthalmic artery ( ICA )
 Sphenopalatine artery, greater palatine artery are
branches of maxillary artery ( ECA )
 Superior labial artery is a branch of facial artery (ECA)

48. Important anatomical
concepts
 the perpendicular plate of ethmoid should NOT
be rocked as it may lead to the fracture of
cribriform plate and cause CSF leak.

49. Lateral wall of nose
 Very important to be anatomically oriented
 With the invent of endoscopy landmarks need to
be well versed
 Makes radiological interpretation very easy

50.  Lateral wall will be dissected layer by layer to get
familiar with anatomical details

51. 3D view of lateral nasal wall

52. Lateral nasal wall

54.  Anterior part is covered by skin and has hair (vestibule)
 Bulge anterior to the middle turbinate is the agger nasi cell
(most anterior ethmoidal cell)
 Ridge from agger nasi cells extend to the superior border of
the inferior turbinate ( naso lacrimal duct)

55.  Most anteriorly is a curved ridge called the
uncinate process.
 Behind this is the well pneumatized and most
constant anterior ethmoidal cell, namely the
ethmoidal bulla.
 These structures are separated by a semilunar
groove called the hiatus semilunaris.

56.  The hiatus semilunaris is two-dimensional and
leads into a three-dimensional space called the
infundibulum.
 The uncinate process, the bulla and the
intervening infundibulum form the key area or the
osteomeatal unit into which the frontal, the
maxillary and anterior ethmoidal sinuses drain.

57. Osteomeatal unit

58.  Minimal inflammation in the osteomeatal area
can block off aeration to the
 anterior ethmoid,
 frontal
 maxillary sinus, leading to infection in them.
 This concept is the basis of Messerklinger’s
functional endoscopic sinus surgery whereby the
clearance of this area alone may reverse
changes in the draining sinuses.

59. applied anatomy
 Middle turbinate should be manipulated very
gently as it attaches directly to the cribriform
plate.
 A forcible attempt to medialize the middle
turbinate in order to get a better view of the
middle meatus may lead to a break in the
cribriform plate and a CSF leak

60.  While dissecting in the region of the frontal recess,
care should be taken to maintain the mucosa
over the middle turbinate.
 adhesions will form between the lateral nasal wall
and the upper attachment of the middle turbinate
 These adhesions will cause lateralization of the
middle turbinate and obliteration of the frontal
recess with subsequent iatrogenic frontal sinus disease
 In extreme cases complete obliteration of the
middle meatus may occur.

61. Middle turbinate excised

63.  The uncinate process is sickle shaped, with
vertical and a horizontal limb
 The ethmoidal bulla is usually a well pneumatized,
most constant, anterior ethmoidal cell.
 Can be absent in 8% of cases

64. Ethmoidal bulla
 separated posteriorly from the ground lamella of the
middle turbinate by a recess called the retrobullar recess
 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.

65. Ethmoidal bulla orientation

66. applied anatomy
 Clearance of the bulla, anterior and posterior
ethmoid cells should be done using blunt instrument
to prevent injury to the lamina papyracea and
orbital contents.
 The anterior wall of the bulla lies just in front of the
anterior ethmoidal artery at the base skull

67. Frontal recess
 Lot of anatomical variations
 bounded anteriorly by the agger nasi cell .
 The posterior wall is formed by the bulla ethmoidalis.
 The lateral wall is formed by the lamina papyracea.
 The medial wall is formed by the middle turbinate.
 Superiorly the frontal recess opens via the frontal ostium
into the frontal sinus.

68. Hour glass configuration of
frontal recess

69. Frontal recess

71. Applied anatomy
 Whilst dissecting in the frontal recess the surgeon
may think he has entered the frontal sinus, when
in fact, he is within a frontal cell (anterior
ethmoidal cell )
 It is necessary to de-roof this frontal cell so as to
reach the frontal sinus and establish its drainage

72. Reflected uncinate process

75. Applied anatomy
 A branch of the sphenopalatine artery runs along
the lateral nasal wall in the middle meatus.
 This branch may be encountered whilst widening
the maxillary ostium posteriorly
 The normal ostium should be widened in an
anteroinferior direction to prevent injury to the
nasolacrimal duct, which lies 5 mm anterior to it.

76.  The sphenoid sinus ostium lies high on its anterior wall
close to its roof.
 It drains into the sphenoethmoidal recess.
 The superior turbinate in the sphenoethmoidal recess,
may over lie the opening of the sphenoid ostium.
 The sphenoid ostium lies 1-1.5 cm above the roof of the
posterior choana and approximately 2-3 mm away from
the septum.

78. Ethmoidal sinus
 The anterior ethmoidal air cells are variable in
number; the posterior ethmoidal air cells are fewer
and larger.
 Anterior group drains into middle meatus by way of
the infundibulum
 Middle group drains into the middle meatus
 Posterior group drains into superior meatus and
some times one or more into sphenoidal sinus

79.  The anterior ethmoidal cells may migrate
anterosuperiorly into the frontal recess to produce
different types of frontal cells
 Type I A single cell above the agger nasi cell
 Type II Two or more cells above the agger nasi cell.
 Type III A large cell extending well into the frontal sinus
mimicking the frontal sinus itself (frontal bulla).
 Type IV An isolated “loner cell” separately within the
frontal sinus

80. Anterior ethmoidal cell migrating
into frontal recess

82.  posterior ethmoidal cell may extend
posterolaterally over the sphenoid called the Onodi cell.
 Thus the Onodi cell insinuates itself between the optic
nerve and the sphenoid sinus.
 The optic nerve therefore produces a bulge in the Onodi
cell instead of in the sphenoid sinus.

83. Posterior ethmoidal cell (
onodi cell )

85. Sphenoidal surgery
 In approximately 6 percent of cases, the bone over the optic nerve
may be dehiscent
 in approximately 25 percent of cases, bone over the internal carotid
artery may be clinically dehiscent.
 This may be difficult to visualize on CT scan if the sphenoid sinus is
full of polyps.
 Therefore extreme caution has to be exercised in pulling polyps out
from within the sphenoid sinus.
 A branch of the sphenopalatine artery runs across the anterior face
of the sphenoid to reach the septum may be injured during widening
the ostium.

86. Removed anterior and
posterior ethmoidal cell

87. 4 lamellae encountered on
endoscopy
 These from anterior to posterior are—
 the uncinate process,
 the anterior wall of the bulla,
 the ground lamella
 the anterior wall of the sphenoid.

89. Complete removal anterior and
posterior ethmoidal cells

91.  The ethmoidal cells have been completely
cleared to expose the lamina papyracea, which
appears yellowish due to the underlying orbital fat
 The maxillary ostium has been widened to gain a
view of the interior of the sinus.
 the lamina papyracea and the orbit is just 2-3 mm
above the level of the maxillary ostium.

92. Nasolacrimal duct is split
with sac and opening

93.  The nasolacrimal duct opens in the roof of the
inferior meatus at this apex.
 It is guarded by a valve called the Hasner’s valve.
 The canal for the nasolacrimal duct has been
dissected. It lies approximately 5 mm anterior to
the normal maxillary ostium.

95. Lamina papyracea removed

96.  The lamina papyracea has been removed and the
orbital periosteum has been cut to expose the orbital fat.
 Anteriorly, a pad of fat separates the vital structures of
the orbit from the nose.
 posteriorly the medial rectus is in close relation with the
lamina papyracea

98. Medial rectus reflected

100. Blood supply of lateral wall
of nose

102. Take home message
 With the incorporation of FESS into ENT speciality
( thanks to Dr. Messerklinger ) the anatomical
orientation is very important.
 The osteocartilagenous framework acts as a
single unit and needs to be respected while
performing surgery.
 Concept of osteomealtal unit could be understood only
when the sinus anatomy and their drainage are well versed.

103. And…. The nose spoke to the
children……
Patch Adams ( 1998 )