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Positioning Ch 22
Paranasal Sinuses
| Question | Answer |
|---|---|
| air-containing cavities that form from the nasal mucosa and communicate with the nasal fossae | paranasal sinuses |
| Name the 4 bones that contain the paranasal sinsuses | *Frontal *Ethmoid *Sphenoid *Maxillary |
| List 5 Functions of the Paranasal Sinuses | *Resonating chamber for the voice *Decrease the weight of the skull by containing air *Warm & moisten inhaled air *Act as shock absorbers in trauma *Possibly control the immune system |
| these sinuses are usually sufficiently well developed and aerated at birth to be demonstrated radiographically | maxillary sinuses |
| these sinuses are distinguishable by age 6 or 7 | the Frontal and Sphenoidal sinuses |
| At what age are all the paranasal sinuses completely developed? | by age 17 |
| these sinuses develop during puberty | the ethmoidal air cells |
| When fully developed, what do each of the sinuses communicate with? | each of the sinuses communicates with the others and with the nasal cavity |
| the largest sinuses | maxillary sinuses |
| these sinuses are approximately pyramidal in shape and have only 3 walls | maxillary sinuses |
| these sinuses communicate with the middle nasal meatus at the superior aspect of the sinus | maxillary sinuses |
| In adults, each of these sinuses is approx. 3.5 cm high and 2.5 to 3 cm wide | maxillary sinuses |
| the second-largest sinuses | frontal sinuses |
| these sinuses are paired and are normally located between the tables of the vertical plate of the frontal bone | frontal sinuses |
| these sinuses vary greatly in size and form and occasionally they are absent | frontal sinuses |
| these sinuses often extend into the orbital plates | frontal sinuses |
| this is usually deviated from the midline in the frontal sinuses; for this reason the frontal sinuses are rarely symmetric | intersinus septum |
| these sinuses sometimes have multiple septa | frontal sinuses |
| Name the sinuses that drain into the middle nasal meatus | *Maxillary sinuses *Frontal sinuses *the Anterior and Middle Ethmoidal cells |
| these sinuses vary considerably in size and shape but are usually symmetric | maxillary sinuses |
| often divided into subcompartments by partial septa, and occasionally it is divided into 2 sinuses by a complete septum | maxillary sinuses |
| located within the lateral masses of the labyrinths of the ethmoid bone | the 2 ethmoidal sinuses |
| composed of a varying number of air cells that are divided into 3 main groups | ethmoidal sinuses |
| Name the 3 main groups of the ethmoidal sinuses | *Anterior *Middle *Posterior |
| these 2 groups of the ethmoidal cells vary in number from 2 to 8 and each group opens into the middle nasal meatus | the Anterior and Middle Ethmoidal cells |
| this group of the ethmoidal cells vary in number from 2 to 6 or more and drain into the superior nasal meatus | the Posterior Ethmoidal cells |
| normally paired and occupy the body of the sphenoid bone | the sphenoidal sinuses |
| only one of these sinuses is often present; however, more than 2 are never present | sphenoidal sinuses |
| vary considerably in size and shape and are usually asymmetric | sphenoidal sinuses |
| They lie immediately below the sellae turcica and extend between the dorsum sellae and the posterior ethmoidal air cells. | sphenoidal sinuses |
| these sinuses open into the sphenoethmoidal recess of the nasal cavity | sphenoidal sinuses |
| Which sinuses are the most commonly infected? | maxillary sinuses |
| What technical factor is probably more critical and more misleading in the sinuses than in any other region of the body? | radiographic density |
| this diminishes or completely obliterates existing pathologic conditions | overpenetration of the sinuses |
| this can stimulate pathologic conditions that do not exist | underpenetration |
| These 2 factors should be balanced so that both soft tissue structures and bony structures are demonstrated | mAs and kVp |
| Although good contrast is desirable, these areas may not be visualized with high contrast | soft tissue areas |
| Whenever possible, radiographs of the paranasal sinuses should be made with the patient in this position. | upright |
| List 2 reasons why the patient should be positioned upright for radiographs of the paranasal sinuses. | *To demonstrate the presence or absence of fluid *To differentiate between fluid and other pathologic conditions |
| Why is a precise technical procedure necessary in radiography of the paranasal sinuses? | Because unless sinus radiographs are almost perfect technically, they are of little diagnostic value. |
| Name 5 Precise Technical Procedures necessary in radiography of the paranasal sinuses. | *Small focal spot *Clean imaging screens w/ perfect contact *Radiographic contrast must similarly distinguish the sinuses from the surrounding structures *The head must be carefully positioned & rigidly immobilized *Respiration suspended for the exposures |
| When the position of a patient is changed or the patient's neck is flexed or extended to position the head for special projections, how much time should be allowed for the exudate to gravitate to the desired location before the exposure is made? | several minutes |
| Although numerous sinus projections are possible, with each serving a special purpose, many are used only when required to demonstrate __________. | a specific lesion |
| Name the 5 standard projections that adequately demonstrate all of the paranasal sinuses in the majority of patients. | *Lateral (R or L) *PA Axial Caldwell Method *Parietoacanthial Waters Method *Parietoacanthial Open Mouth Waters Method *SMV |
| Name 3 steps to prepare for the projections of the paranasal sinuses: | *Use a protractor to ensure accurate positioning *Have patient remove dentures, hairpins, earrings, necklaces, etc. (also no wet hair or braids) *Clean the IR before positioning patient |
| How can medical asepsis be promoted when positioning the patient for paranasal sinus projections? | by placing a paper towel or sheet between the imaging surface and the patient |
| As a standard procedure, when should the contacted area be cleaned with a disinfectant? | before and after positioning |
| What is the most effective way to protect the patient from unnecessary radiation during paranasal sinus exams? | restricting the radiation beam by using proper collimation |
| True or False: One of the functions of the sinuses is to increase the weight of the skull. | False |
| Which sinus is located in the most superior position in the skull? | Frontal sinuses |
| The Ethmoidal sinuses are located in the _______. | cranium |
| True or False: Proper patient instructions before the examination will assist in radiation protection for a patient receiving sinus radiographs. | True |
| True or False: Sinus radiographs should be made in the semi erect position to be visualize air fluid levels. | False |
| Which sinus is the largest? | Maxillary |
| True or False: Proper collimation to the appropriate anatomy is one of the ways to protect the patient from unnecessary radiation during sinus radiography | True |
| True or False: At birth, the frontal sinuses are sufficiently developed and aerated and can be radiographed. | False |
| Which projections will demonstrate the ethmoidal sinuses? | *PA Axial Caldwell *SMV |
| For the lateral sinus projection, this line is positioned horizontally to ensure proper extension of the head. | IOML |
| For the lateral projection, which line is parallel with the transverse axis of the vertical grid device? | IOML |
| For the lateral sinus projection, how is the central ray directed? | horizontally |
| Where on the patient's head should the central ray be directed for the lateral sinus projection? | 1/2 to 1 inch posterior to the outer canthus |
| Structures shown on the lateral sinus projection: | *the AP and superoinferior dimensions of the paranasal sinuses *their relationship to surrounding structures *the thickness of the outer table of the frontal bone |
| When the lateral projection of the sinuses is to be used for preoperative measurements, what SID should be used to minimize magnification and distortion? | 72 inch SID |
| If the patient is unable to assume the upright body position, a lateral projection for the sinuses can be obtained using this position | dorsal decubitus |
| What is the preferred grid technique for the PA Axial Caldwell Method projection? Why? | the angled grid technique, because it brings the IR closer to the sinuses, increasing resolution; also provides a natural position for the placement of the patient's nose and forehead |
| These structures are demonstrated with the Waters Method and can be seen, one on each side, just inferior to the medial aspect of the orbital floor and superior to the roof of the maxillary sinuses | foramen rotundum |
| This projection can be used to demonstrate retention cyst and nasal deviation | Waters Method |
| This projection best demonstrates inflamatory changes in the frontal sinuses and the anterior ethmoid sinuses. | Caldwell Method |
Created by:
foster1317