Transcript Paranasal Sinuses - El Camino College

Paranasal Sinuses
Week 10
Anterior Sinus Anatomy

Purpose of sinuses

Resonating chamber
for voice

Decrease weight of
skull

Warm & moisten air

Shock absorbers

Immune system
Lateral Sinus Anatomy

Aerated at birth


Age 6-7


Maxillary sinuses
Frontal
/sphenoidal
sinuses
Puberty- approx
17-18 yrs

Ethmoid
Maxillary Sinuses

Largest sinuses



3.5 cm high
2.5 – 3 cm wide
Within maxilla

Above upper teeth

Paired & symmetric

Communicates with
middle nasal meatus
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Frontal Sinuses

Second largest sinuses


2 – 2.5 cm
Normally:


Between tables of
vertical plate in frontal
bone
Can extend beyond
frontal bone inot the
orbital plates

Rarely symmetrical

Number varies
(occassionally absent)

Drain into middle nasal
meatus
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Sphenoid Sinuses

Below sella turcica


Can be single or paired


Extends between
dorsum sellae and
post clinoid processes
Usually no more than
two
Drains into
sphenoethmoidal
recess of nasal cavity
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Ethmoid Sinuses

Within lateral masses
of ethmoid bone

Three groups:


Anterior & middle



Anterior, middle &
posterior
2-8 cells
Drains into middle
nasal meatus
Posterior


2-6 cells
Drain into superior
nasal meatus
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Osteomeatal complex –
coronal view

Pathways of
communication


Frontal, ethmoid
and maxillary
2 key passageways


Infundibulum
Middle nasal
meatus
Osteomeatal Complex
Paranasal Sinuses
Protocols

Lateral

PA (Caldwell)

Parietoacanthial (Waters)

Parietoacanthial (Open mouth Waters)

SMV
Technical Considerations

Radiographic density is critical


Overpenetration diminishes or obliterates
patholgy
Underpenetration can simulate pathology

Small focal spot

Clean screens

Perfect film/screen contact

No high contrast
Air Fluid Levels
Pathologic Indications

Inflammatory conditions:

Sinusitis
• Acute
• Chronic

Secondary Osteomyelitis

Sinus Polyps

Trauma
Lateral Projection

Upright or cross table

IPL perp to IR

MSP and IOML parallel
to IR

CR horizontal entering
½ - 1” post to outer
canthus

Suspend respiration
Lateral Sinuses
Lateral Radiograph

All 4 sinuses

Sphenoid of primary
interest

No rotation

SI orbital roofs,
mandibular rami

Close beam restriction

Clear air-fluid levels
Caldwell

Seated upright

Angled grid 15
degrees:



OML & MSP perp
Nose & forehead
Vertical grid:


Tip of nose on grid
and use sponge
OML 15 from CR

CR horizontal to exit
nasion

Suspend respiration
Caldwell Radiograph
Frontal & Anterior ethmoid

No rotation

Petrous ridges symmetric

Petrous ridge in lower 1/3 of
orbits

Frontal sinus above
frontonasal suture

Anterior ethmoid cells above
petrous ridges

Frontal &ethmoid air cells

Air fluid levels

Close beam restriction
Waters for Maxillary sinuses

Upright

Chin on IR

MSP &MML perp

OML 37 degrees

Suspend respiration

CR horizontal and
exiting acanthion
Waters
Waters Radiograph

Petrose just below
maxillary sinuses

No rotation

Orbits & maxillary
sinuses symmetric

Close beam
restriction

Clear air-fluid levels
Open Mouth Waters for
Maxillary / sphenoid sinuses

Upright

Chin on grid

OML 37 degrees

Open mouth

Suspend respiration

CR horizontal and
exiting acanthion
Open mouth Waters
Radiograph

Petrous ridges below
maxillary sinuses

No rotation

Maxillary sinuses

Close beam restriction

Clear air-fluid levels

Sphenoid sinuses
through open mouth
SMV for ethmoidal and
sphenoidal sinuses

Seated upright

IOML parallel to IR

Backed strip of adhesive
tape

Suspend respiration

CR horizontal and perp to
IOML through the sella
turcica

CR enters MSP ¾”
anterior to level of EAM
SMV Sinuses
SMV Radiograph

No tilt or rotation

Anterior frontal
bone SI over
mental
protuberance

Mandibular
condyles anterior to
petrous pyramids

Clear air-fluid levels
Acute Sinusitis
Acute Sinusitis
Mucous Retention Cysts
Tripod Fracture
Chronic Sinusitis

MMT: mucous
membrane thickening

OFS: opacified frontal
sinus

OES: opacified
ethmoid sinus

OMS: opacified
maxillary sinus

M: mucocoele