Sinuses Flashcards
The paranasal sinuses are 4 groups of air containing cavities:
within the cranium: Ethmoid bone, sphenoid bone, and frontal bone. Within the facial bones: maxillary bone.
Each sinus communicates with:
the nasal cavity
Each sinus is lined with:
a mucous membrane.
Functions for paranasal sinuses are believed to be:
resonating chamber for voice. decrease weight of skull. warm and moisten inhaled air. shock absorbers in trauma (like air bags) possibly control immune system.
The paranasal sinuses begin to develop in the fetus, but only the ______ sinuses are demonstrated radiographically at birth.
maxillary
______ & ________ sinuses are visible radiographically at 6 or 7 years old.
Frontal and sphenoid.
______ sinuses are fully developed by late teenage years
Ethmoid
Maxillary sinuses are located:
in the body of each maxillary bone.
Older terms for maxillary sinuses include:
Antrum or Antrum of Highmore
The maxillary sinuses are shaped:
like pyramids in the front and cube-shaped from the side.
Infections starting within the first and second upper molar teeth can spread where? How?
Projecting in to the floor of each maxillary sinus are several conic elevations related to roots of the first and second upper molar feet. Infections in these teeth can therefore spread upward into the maxillary sinuses.
All paranasal sinuses communicate with:
each other and with the nasal cavity which is divided in to two fossae.
The site of communication in the maxillary sinuses is:
the opening to the middle nasal meatus passageway.
Because mucus or fluid trapped in sinuses tend to layer out and form an air-fluid level,
all radiographic positioning for sinuses should be performed in the upright position.
Frontal sinuses are located:
between the inner and outer tables of skull posterior to glabella
The frontal sinuses are rarely aerated before the age of:
6.
The frontal sinuses vary in:
size and are occasionally absent.
Generally the frontal sinuses are two cavities separated by:
a septum, but may be one cavity.
The fontal sinuses are generally larger in:
men.
Ethmoid sinuses are contained:
within lateral masses (labyrinths) of ethmoid.
The ethmoid sinuses are divided into three groups:
Anterior, middle, posterior. All intercommunicate.
Sphenoid sinuses lie in:
body of sphenoid directly below the sella turcica.
The sphenoid sinuses extend between:
posterior ethmoids and dorsum sella.
True or false? The sphenoid sinuses are paired.
True, but can be single. When paired, they are separated by a septum.
The sphenoid sinuses are very close to:
the base of the skull. Air-fluid levels could indicate basal skull fracture after trauma indicating blood or CSF is leaking through fracture into sphenoid sinus (sphenoid effusion)
The osteomeatal complex is:
the pathways of communication between the frontal, maxillary and ethmoid sinuses which provide drainage between them.
An obstructed osteomeatal complex leads to:
infection or sinusitis.
Osteomeatal complex can be imaged with:
CT
The two key passageway of the osteomeatal complex are:
infundibulum and middle nasal meatus.
The maxillary sinuses drain through:
the infundibulum passageway to the middle nasal meatus into the inferior nasal meatus.
The frontal and ethomoid sinuses use drain into the:
ethmoid bulla and then drain through middl nasal meatus into inferior nasal meatus.
On a lateral view, the frontal sinuses are visualized:
between the inner and outer table of skull.
On a lateral view, the sphenoid sinuses appear:
continuous with the ethmoid sinuses.
On a lateral view, roots of the upper teeth appear to extend up through the floor of:
the maxillary sinuses.
A PA (Caldwell) position best demonstrates which sinuses?
Frontal and anterior ethmoid sinuses.
A PA axial (open mouth waters) position is performed so:
sphenoid sinus projects into open mouth.
A submentovertex (SMV) projection shows the sphenoid sinus located:
anterior to the foramen magnum.
On a SMV projection, the ethmoid sinuses are located:
to each side of nasal septum.
On SMV projection, the mandible and teeth superimpose most of:
maxillary sinuses.
The 14 facial bones are:
Two nasal bones, two lacrimal bones, two zygomas, two nasal conchae, two maxilla, one mandible, two palatine bones, vomer.
The lateral masses of the ethmoid bone form:
the medial wall of the obit.
On a lateral projection, the ethmoids fill:
the orbits
The facial bones form several cavities, three of which are:
oral cavity, nasal cavity, and orbits.
Long axis of orbit projects superiorly ___ degrees and projects medially ___ degrees.
30 and 37.
The base of the orbit is made up of these three bones:
The orbital plates of the frontal bone, the zygoma and the maxilla.
What 3 cranial bones and 4 facial bones make up the bones of the orbits?
Ethmoid, frontal and sphenoid are the three cranial bones. The lacrimal, maxillary, palatine and zygomatic bones are the facial bones.
The openings in the orbits are:
The optic foramen, the superior orbital fissure and the inferior orbital fissure.
The parietoorbital oblique projection of the orbits shows the following anatomy:
Orbital plate of the frontal bone Sphenoid bone Optic foramen and canal Superior orbital fissure Infraorbital margin Sphenoid strut Lateral orbital margin Supraorbital margin
Which of the following facial bones is unpaired? Maxillary Palatine Lacrimal Vomer
Vomer
The anterior nasal spine is an aspect of the ______ bone.
Maxillary
The palatine process is an aspect of the ____ bone.
Maxillary
Lacrimal is derived from a word meaning:
Tear
Which facial bone forms an aspect of the bony nasal septum?
Vomer
What is the name of the process of the mandible in which the lower teeth are embedded?
Alveolar process
The older term “antrum of Highmore” describes the:
Maxillary sinuses
Which paranasal sinus is the last one to develop?
ethmoid
The posterior aspect of the bony orbit is termed the:
Apex
Which of the following bones makes up most of the lateral wall of the orbit? Maxillary Lacrimal Zygomatic Vomer
zygomatic
What passes through the optic foramen?
The second cranial nerve (the optic nerve)
Radiographic exams of the sinuses are performed to demonstrate:
mucosal thickening
air-fluid levels
erosion of bony margins.
Blowout fracture:
- Fracture of floor of orbit.
- Caused by object striking eyes straight on.
- Floor ruptures and the inferior rectus muscle is forced through fracture and into maxillary sinus causing entrapment and diplopia.
Tripod fracture:
Caused by blow to cheek.
The zygoma fractures at the orbital process, maxillary process and temporal process, causing a free-floating zygomatic bone
LeForte fractures:
Severe bilateral horizontal fractures of maxillae which may result in unstable detached fragment.
Countrecoup:
Injury/fracture to one side of a structure caused by an impact on the opposite side.
Foreign body of the eye:
Metal or other types of fragments in the eye.
Plain images detect presence of metallic foreign objects but are limited in ability to demonstrate damage.
Neoplasm
new and abnormal growth that may occur in skeletal structures of face.
Osteomyelitis:
Localized infection of bone/bone marrow caused by bacteria from penetrating trauma, postoperative or fracture complication. Spread by flood from distant site.
Sinusitis:
Infection of sinus mucosa. Can be acute or chronic. Symptoms include headache, pain, swelling over affected sinus and possible low grade fever.
Secondary osteomyelitis:
Infection of bone and marry secondary to sinusitis. Results in erosion of bony margins of sinus.
TMJ Syndrome:
Describes a set of symptoms which may include pain and clicking that indicate dysfunction of the TMJ. Causes include malocclusion, stress, muscle spasm or inflammation.
Clinical indications of facial and paranasal sinuses:
Blowout fracture, Tripod fracture, LeForte fracture, Contrecoup, Foreign body of the eye neoplasm, osteomyelitis, sinusitis, secondary osteomyelitis, TMJ syndrome.
Erect position for facial bones and paranasal sinuses allows for _______ and permits use of horizontal beam to demonstrate:
patient to be quickly and easily positioned.
air/fluid levels within sinus cavities
Respiration suspended during exposure except in cases of
severe trauma
Cranial and facial radiography requires patient’s face to be in direct contact with radiographer’s hands and table/upright Bucky surface, therefore,
wash hands and sanitize table/Bucky before and after every exam.
Exposure Factors for Cranium and Facial Bones:
Medium kV (65 to 85 analog); (75 to 90 kV digital systems)
Small focal spot less than 200 mA
Short exposure time
Minimum SID 40” (102 cm)
Exposure Factors for Paranasal Sinuses:
Medium kV (65 to 85 analog); (75 to 90 kV digital systems) commonly used to provide sufficient contrast
Optimal density (mAs) to visualize pathology in sinuses
Small focal spot for maximum detail
Minimum SID 40” (102 cm)
To ensure Radiation Protection:
close collimation
Minimize repeats (Immobilization)
Center properly
Shielding of radiosensitive organs recommended
Five Common Positioning Errors
Rotation Tilt Excessive flexion Excessive extension Incorrect CR angle
To prevent superior or inferior pull on head resulting in angulation or tilt:
Place patient’s body so long axis of cervical vertebrae coincides with level of foramen magnum
