Radiographic Procedures II Skull, Orbits, Paranasal Sinuses

The skull is comprised of

22 bones, 8 cranial bones, and 14 facial bones

Calvaria is composed of

frontal bone, 2 parietal bones, occipital bone

The OML forms an angle of how many degrees from the plane of the image receptor for an open-mouth parietoacanthial (waters method) projections?

37 degrees

How many bones compose the bony orbit?

7

Where are the petrous ridges seen on an image of parietoacanthial (waters method) projection of the paranasal sinuses?

Inferior to the floor of the maxillary sinuses

The thickest and densest portion of bone in the cranium is the:

petrous portion of the temporal bone

Where is the image receptor centered for the parietoacanthial (Waters method) projection of the sinuses?

Acanthion

The central ray angle for the PA axial (Caldwell) projection of the skull is:

15 degrees caudad

The central ray and center of the IR position for a lateral projection of the skull is__________inches________the EAM

2 inches above

Which reference line is positioned perpendicular to the angled image receptor for the PA axial (Caldwell) method projection of the sinuses?

OML

Which two must occur to successfully demonstrate the ethmoidal and sphenoidal sinuses on the SMV projection? (Select all that apply.)

Central ray aligned horizontal and enters perpendicular to IOML.

3 multiple choice options

The six areas of incomplete ossification in a newborn infant's skull are called the:

fontanels

The parietoacnathial projection (waters method) of the orbits for foreign body is often modified so that there is less angulation of the facial bones. For this modification, the orbitomeatal line is adjusted to:

50 degrees

Which sinus is located immediately below the Sella turcica?

Sphenoidal

Which of the following lines should be placed perpendicular to the image receptor plane. when a 30 degree angulation is employed, for the AP axial Towne projection?

OML

Radiographic demonstration of the cranial base is performed by which method?

Schuller

The paranasal sinuses should always be examined in the upright position to:

demonstrate the presence or absence of fluid and differentiate between fluid and other pathologic conditions

At which level should the central ray enter the base of the skull for the SMV projection of the sinuses?

At the level of the gonion

Which two are clearly demonstrated within the foramen magnum during an AP axial Towne projection of the skull?

Dorsum sellae and posterior clinoid

Which of the following skull types is considered average in size and shape?

Mesocephalic

What is the average central ray angulation for the PA axial Haas projection of the skull?

25 degrees cephalad

Which two methods will clearly demonstrate the petrous ridges, foramen magnum, dorsum sellae, and posterior clinoid processes?

Towne AP axial and Haas PA axial

Which simus is projected through the mouth on the open mouth modification of the Waters method?

Sphenoid

The central ray forms an angle of how many degrees with the OML for the PA axial Caldwell vertical grid technique projection of the sinuses?

15 degrees

Often a patient cannot be turned into the prone position for a PA axial projection of the skull Caldwell method. What central ray angle would be used if the AP axial projection is used instead?

15 degrees cephalic

For a lateral projection of the paranasal sinuses, the central ray is directed:

0.5-1 inch posterior to outer canthus

Which projection of the skull requires MSP be positioned parallel and interpupillary line perpendicular to the IR plane?

Lateral

Which method of examining the skull will demonstrate the petrous ridges in the lower one third of the orbits and the frontal sinuses?

Caldwell

The landmark underneath the nose:

Acanthion

The petromastoid portion is part of which bones?

Temporal

How many bones make up the cranium?

8

The respiration phase for all projections of the skull and sinuses is:

suspended

The central ray directed perpendicular to which reference line for the SMV projection of the sinuses?

IOML

Which of the following reference lines is placed perpendicular to the image receptor for a parietoacantial waters method projection of the orbits?

MML

The cranial bones are rigidly joined together by articulations called:

Sutures

In a typically shaped head, the petrous pyramids project anteriorly and medially at what angled?

47 degrees

Which two parts of the patients face touch the table for a PA axial projection Caldwell method of the skull?

Nose and forehead

Which of the following is perpendicular to the image receptor plane for a Caldwell projection of the skull?

OML

For an SMV projection of the cranial base, the central ray should always be perpendicular to the ____ line.

IOML

Which line should be placed parallel to the plane of the IR for the SMV projection of the cranial base?

IOML

Which plane of the head is placed parallel to the plane of the image receptor for a lateral projection of the skull?

Midsagittal

Which of the following is (are) true regarding positioning for the waters method for the orbital evaluation for foreign body?

The OML forms a 37 degree angle with the plane of the IR and MSP perpendicular to the IR plane

The landmark at the top/bridge of nose:

nasion

Which skull type is narrow from side to side?

Dolichocephalic

Which reference line is positioned horizontal to long axis of the IR to ensure proper extension of the head during a lateral projection of the sinuses?

IOML