Head - Rad Review

Which of the following structures should be visualized through the foramen magnum in an AP axial projection (Towne method) of the skull for occipital bone? 1. Posterior clinoid processes 2. Dorsum sella 3. Posterior arch of C1

1 and 2 only -The AP axial projection (Towne method) of the skull requires that the CR be angled 30 degrees caudad if the OML is perpendicular to the IR (37 degrees caudad if the IOML is perpendicular to the IR). The frontal and facial bones are projected down and away from superimposition on the occipital bone. If positioning is accurate, the dorsum sella and posterior clinoid processes will be demonstrated within the foramen magnum. If the CR is angled excessively, the posterior aspect of the arch of C1 will appear in the foramen magnum.

Which of the following positions is/are most frequently used to demonstrate the sphenoid sinuses? 1. Modified Waters (mouth open) 2. Lateral 3. PA axial

1 and 2 only -The parietoacanthal (Waters method) projection demonstrates the maxillary sinuses. The modified Waters position, with the CR directed through the open mouth, will demonstrate the sphenoid sinuses through the open mouth. The PA axial projection demonstrates the frontal and ethmoidal sinus groups. The lateral projection, with the CR entering 1 inch posterior to the outer canthus, demonstrates all the paranasal sinuses. X-ray examinations of the sinuses always should be performed erect to demonstrate leveling of any fluid present.

The true lateral position of the skull uses which of the following principles? 1. Interpupillary line perpendicular to the IR 2. MSP perpendicular to the IR 3. Infraorbitomeatal line (IOML) parallel to the transverse axis of the IR

1 and 3 only -A lateral projection generally is included in a routine skull series. The patient is placed in a PA oblique position. The MSP is positioned parallel to the IR, and the IOML is adjusted so as to be parallel to the long axis of the cassette. The interpupillary line must be perpendicular to the IR. In a routine lateral projection of the skull, the CR should enter approximately 2 inches superior to the EAM.

Which of the following statements is (are) true regarding a PA projection of the paranasal sinuses? 1. The OML is elevated 15 degrees from the horizontal. 2. The petrous pyramids completely fill the orbits. 3. The frontal and ethmoidal sinuses are visualized.

1 and 3 only -The PA (Caldwell) projection of the paranasal sinuses is used to demonstrate the frontal and ethmoidal sinuses. The patient's skull is placed PA, and the OML is elevated 15 degrees from the horizontal. This projects the petrous pyramids into the lower third of the orbits, thus permitting optimal visualization of the frontal and ethmoidal sinuses.

Which of the following statements is (are) correct regarding the parietoacanthial projection (Waters' method) of the skull? 1. The head is rested on the extended chin. 2. The orbitomeatal line (OML) is perpendicular to the (IR). 3. The maxillary antra should be projected above the petrosa.

1 and 3 only -The parietoacanthial projection (Waters' position) of the skull is valuable for the demonstration of facial bones or maxillary sinuses. The head is rested on the extended chin so that the OML forms a 37° angle with the IR. This projects the petrous pyramids below the floor of the maxillary sinuses and provides an oblique frontal view of the facial bones

When evaluating a PA axial projection of the skull with a 15-degree caudal angle, the radiographer should see 1. petrous pyramids in the lower third of the orbits 2. equal distance from the lateral border of the skull to the lateral rim of the orbit bilaterally 3. symmetrical petrous pyramids

1, 2, and 3 -A PA axial projection of the skull with a 15-degree caudad angle will show the petrous pyramids in the lower third of the orbits. If no angulation is used, the petrous pyramids will fill the orbits. Either PA projection should demonstrate symmetrical petrous pyramids and an equal distance from the lateral border of the skull to the lateral border of the orbit on both sides. This determines that there is no rotation of the skull.

Angulation of the central ray may be required 1. to avoid superimposition of overlying structures. 2. to avoid foreshortening or self-superimposition. 3. to project through certain articulations.

1, 2, and 3 -If structures are overlying or underlying the area to be demonstrated (eg, the medial femoral condyle obscuring the joint space in the lateral knee projection), central ray angulation is employed (eg, 5° cephalad angulation to see the joint space in the lateral knee). If structures would be foreshortened or self-superimposed (eg, the scaphoid in a PA wrist), central ray angulation may be employed to place the structure more closely parallel with the IR. Another example is the oblique cervical spine, where cephalad or caudad angulation is required to "open" the intervertebral foramina

In a lateral projection of the nasal bones, the CR is directed?

1/2 inch distal to the nasion

The submentovertical (SMV) oblique axial projection of the zygomatic arches requires that the skull be rotated?

15 degrees toward the affected side -The oblique axial projection is valuable when the zygomatic arches cannot be demonstrated bilaterally with the submentovertical projection because they are not prominent enough or because of a depressed fracture. The patient still may be positioned as for an SMV projection, but the head is obliqued 15 degrees toward the side being examined. This serves to move the zygomatic arch away from superimposed structures and provides a slightly oblique axial projection of the arch

The four major arteries supplying the brain include the 1. brachiocephalic artery 2. common carotid arteries 3. vertebral arteries

2 and 3 only -Major branches of the common carotid arteries (internal carotids) function to supply the anterior brain, whereas the posterior brain is supplied by the vertebral arteries (branches of the subclavian artery). The brachiocephalic (innominate) artery is unpaired and is one of the three branches of the aortic arch, from which the right common carotid artery is derived. The left common carotid artery comes directly off the aortic arch.

The floor of the cranium includes all the following bones except A. the temporal bones B. the occipital bone C. the ethmoid bone D. the sphenoid bone

B. the occipital bone -The skull is divided into two parts—the cranial bones and the facial bones. There are eight cranial bones. Four of them comprise the calvarium—the frontal, the two parietals, and the occipital. The bones that comprise the floor of the cranium are the two temporals, the ethmoid, and the sphenoid

If your patient is unable to stay erect for a paranasal sinus examination, which of the following alternatives should be chosen? A. Recumbent AP B. Lateral recumbent C. Lateral cross-table recumbent D. Recumbent Waters'

C. Lateral cross-table recumbent -Radiography of the paranasal sinuses should be performed in the erect position whenever possible to demonstrate the presence of an air-fluid level. The only way air-fluid levels can be demonstrated is to have the central ray parallel the floor, as in erect, decubitus, and cross-table projections. Therefore, of the choices provided, the cross-table lateral is the only one that will demonstrate air-fluid levels.

Lateral deviation of the nasal septum may be best demonstrated in the A. lateral projection B. PA axial (Caldwell method) projection C. parietoacanthal (Waters method) projection D. AP axial (Towne method) projection

C. parietoacanthal (Waters method) projection -The full length of the nasal septum is best demonstrated in the parietoacanthal (Waters method) projection. This is also the single best view for facial bones. The PA axial (Caldwell method) projection superimposes the petrous structures over the nasal septum, whereas the lateral projection superimposes and obscures good visualization of the septum. The AP axial projection is used to demonstrate the occipital bone

Which of the following skull positions will demonstrate the cranial base, sphenoidal sinuses, atlas, and odontoid process? A. AP axial B. Lateral C. Parietoacanthial D. Submentovertical (SMV)

D. Submentovertical (SMV) -The SMV projection is made with the patient's head resting on the vertex and the CR directed perpendicular to the IOML. This position may be used as part of a sinus survey to demonstrate the sphenoidal sinuses or as a view of the cranial base for the basal foramina (especially the foramina ovale and spinosum). It also demonstrates the bony part of the auditory (eustachian) tubes. AP or PA axial projections are used frequently to demonstrate the occipital region or evaluate the sellar region. A lateral projection is usually part of a routine skull evaluation. The parietoacanthal projection is the single best position to demonstrate facial bones.

Which of the following positions demonstrates all the paranasal sinuses?

Lateral -The parietoacanthial (Waters' method) projection demonstrates the maxillary sinuses. The PA axial with a caudal central ray (Caldwell) demonstrates the frontal and ethmoidal sinus groups. The lateral projection, with the central ray entering 1 inch posterior to the outer canthus, demonstrates all the paranasal sinuses. X-ray examinations of the sinuses should always be performed erect, to demonstrate leveling of any fluid present.

With the patient's head in a PA position and the CR directed 20 degrees cephalad, which part of the mandible will be best visualized?

Rami -With the patient in the PA position, the rami are well visualized with a perpendicular ray or with 20 to 25 degrees of cephalad angulation. A portion of the mandibular body is demonstrated in this position, but most of it is superimposed over the cervical spine.

Which of the following sinus groups is demonstrated with the patient positioned as for a parietoacanthal projection (Waters method) with the CR directed through the patient's open mouth?

Sphenoidal -This is a modification of the parietoacanthal projection (Waters method) in which the patient is requested to open the mouth, and then the skull is positioned so that the OML forms a 37-degree angle with the IR. The CR is directed through the sphenoidal sinuses and exits the open mouth. The routine parietoacanthal projection (with mouth closed) is used to demonstrate the maxillary sinuses projected above the petrous pyramids. The frontal and ethmoidal sinuses are best visualized in the PA axial position (modified Caldwell method).

The auditory, or eustachian, tube extends from the nasopharynx to the?

middle ear