Radiographic Techniques: Facial Bones & Sinuses

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Questions and Answers

What is the primary positioning method for the patient when using a horizontal beam for sinus imaging?

Standing with back against the Bucky

Seated upright with arms crossed

Sitting with legs hanging off the edge

Lying supine with arms extended at sides (correct)

How can it be determined if the skull is not rotated during imaging?

Ensuring the patient's eyes are closed

Checking for symmetry in the facial features

Measuring the distance from a midline point to lateral orbital margins (correct)

Assessing the alignment of the patient's spine

Where should the center of the receptor be positioned during the supine method of imaging?

On the forehead of the patient

2.5 cm inferior to the outer canthus of the eye (correct)

At the level of the outer canthus of the eye

3 cm above the outer canthus of the eye

What anatomical structures does the occipito-mental (OM) projection primarily show?

Nasal region, maxillae, inferior parts of frontal and zygomatic bones Signup and view all the answers

What angle should the interorbital line be in relation to the Bucky/receptor?

At right angles to the Bucky/receptor Signup and view all the answers

Which feature should be included in the image to confirm it contains all relevant sinuses?

Facial bones and the frontal sinus Signup and view all the answers

How is the patient's head positioned for the occipito-mental projection?

At a 45° angle to the Bucky/receptor Signup and view all the answers

What ensures that there is no rotation in an X-ray image for the occipito-mental projection?

Distance from lateral orbital wall to outer skull margins being equidistant Signup and view all the answers

What specific characteristic defines a true lateral position in sinus imaging?

Superimposition of lateral portions of the anterior cranial fossa floor Signup and view all the answers

What factor should be ensured regarding the height of the Bucky/receptor during imaging?

Its center should be lower than the outer canthus of the eye Signup and view all the answers

In the frontal and ethmoid sinus projection, how is the head positioned relative to the horizontal line?

Raised 15° to the horizontal Signup and view all the answers

During imaging, what should be avoided to ensure an accurate representation of the skull?

Rotating the skull Signup and view all the answers

Where should the central ray be directed for the frontal and ethmoid sinus projection?

Perpendicular to the vertical Bucky at the nasion Signup and view all the answers

What is the best position for the patient when performing the occipito-mental projection?

Seated facing the Bucky/receptor Signup and view all the answers

What should be the collimated horizontal beam's positioning relative to the patient's anatomy for the OM projection?

Centered to the Bucky/receptor before positioning Signup and view all the answers

What is a key essential image characteristic for an occipito-mental projection?

Petrous ridges demonstrated inferior to the maxillary sinuses Signup and view all the answers

Study Notes

Radiographic Techniques: Facial Bones and Sinuses

Lecture 3, focusing on facial bones and sinuses.
Includes various radiographic projections, emphasizing different views.

Facial Bones and Sinuses

Diagrams (Figs. 8.25a, 8.25b) illustrate skull structures, showing frontal sinuses, ethmoid sinuses, floor of the anterior cranial fossa, sphenoid sinuses, maxillary sinuses, zygomatic arch, anterior nasal spine, and other important structures.
A labeled radiograph (Fig. 8.26a) visually represents key anatomical structures like outer skull margin, zygomatic arch, petrous ridges, and symphysis menti.
Additional labeled radiographs (Figs. 8.26b and 8.26c) display further details, including soft tissue, inferior orbital margin, frontal sinuses, sphenoid sinuses, and maxillary sinuses.

Occipito-Mental Projection (Fig. 8.28a)

This projection highlights the floor of the orbits, nasal region, maxillae, inferior portions of the frontal bone, and zygomatic bone.
The projection aims to position the petrous portions of the temporal bone below the inferior maxilla, preventing interference on the facial bone image.

Occipito-Mental Projection: Patient and Image Receptor Positioning

Patient should be positioned erect, facing the Bucky/receptor.
Nose and chin should be in contact with the Bucky/receptor's midline.
Adjust the head to ensure the orbito-meatal baseline forms a 45-degree angle with the Bucky/receptor.
The horizontal central line of the Bucky/receptor should align with the lower orbital margins.
Ensure the median sagittal plane of the patient is perpendicular to the Bucky/receptor.

Occipito-Mental Projection: X-ray Beam Direction and Location

The collimated horizontal beam is centered on the Bucky/receptor before positioning.
The beam's crosslines on the Bucky/receptor should align with the patient's anterior nasal spine.
The petrous ridges should be displayed inferior to the maxillary sinus floors.
Rotation should be avoided; lateral orbital wall distances from the outer skull margins should be equal on both sides.

Occipito-Frontal Sinuses

This projection demonstrates frontal and ethmoid sinuses.
Position the patient facing the vertical Bucky/skull unit, ensuring the median sagittal plane aligns with the Bucky's midline, perpendicular to the unit.
Raise the orbito-meatal baseline to 15 degrees from the horizontal.
Ensure the nasion is centered on the Bucky.

Occipito-Frontal Sinuses: X-ray Beam Direction and Location

The central ray should be perpendicular to the Bucky's vertical axis, running along the median sagittal plane, exiting at the nasion.
Collimation should encompass the frontal and ethmoidal sinuses, though sinus size varies between individuals.
All relevant sinuses should be visualized in the image.
Ensure no rotation of the skull to prevent distortion, which may be evaluated by comparing distances from midline to lateral orbital margins on both sides.

Lateral Projection (Figs. 8.32a, 8.32b)

Used to specifically evaluate facial bone injuries in cases of trauma, always using horizontal beams.
Patients can be positioned either erect or supine.

Lateral Projection: Erect Positioning

Patient sits facing the vertical Bucky/receptor.
The side under examination must contact the Bucky/receptor.
Extend the arm on the same side for stability.
The Bucky/receptor height is adjusted so its center is 2.5 cm below the outer canthus of the eye.

Lateral Projection: Supine Positioning

The patient lies on the trolley, arms extended, median sagittal plane vertical to the trolley top (supine).
The CR cassette supports the side under examination; center aligned 2.5cm below the outer canthus.
Interorbital line should be perpendicular to the Bucky/receptor for a true lateral.

Lateral Projection: Essential Image Characteristics

All facial bones and sinuses, including the frontal sinus, must be visualized without distortion.
Anterior cranial fossa's lateral portions must not be superimposed in a true lateral view.

Nasal Bones (Figs. 8.35a, 8.35b)

Positioning: Patient faces 18x24cm cassette in vertical Bucky unit. Head aligned so the median sagittal plane is parallel and interpupillary line perpendicular to the image receptor. The nose should roughly center the image.
Direction: Horizontal central ray of x ray through the nasal bone center, collimating the nose.

Nasal Bones: Image Characteristics

The image should depict nasal bones, soft tissues, frontonasal suture, and anterior nasal spine.
The image of the nasal bones should be obtained without rotation.
Exposure should be suitable for clear visualization of nasal bone and soft tissues. Sharp bony details verify no image motion.

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Description

This quiz covers Lecture 3 on radiographic techniques focusing on the facial bones and sinuses. It includes various projections and diagrams to help understand the anatomical structures such as sinuses, zygomatic arch, and the anterior cranial fossa. Test your knowledge on the essential views and labeled radiographs presented in the lecture.