Radiographic Procedures CH 11 Skull Exam

Ch 11 Bontrager's

Which sinuses are best demonstrated on the parietoacanthial projection (Waters method)?

Maxillary sinuses

Which sinuses are best demonstrated on the PA axial projection (Caldwell method)?

Frontal sinuses

Which of the facial bones form part of the hard palate?

Palatine

All of the following are part of the bony orbit except:

1) Palatine

2) Zygoma

3) Lacrimal

4) Vomer

4) Vomer

What is the CR orientation for an SMV projection of the zygomatic arches?

Perpendicular to IR

What positioning error is present if the mandibular condyles are seen within the petrous portion of the temporal bone on an SMV projection?

Insufficient extension

Which projection of the skull would best detect a fracture of the orbital floor?

Parietoacanthial (Water’s) projection

What is the angle between the OML and the plan of the IR for a parietoacanthial (Water’s) projection of the facial bones?

55 degrees

A fracture of the floor of the orbit caused by an object striking the eyes straight on is termed a:

Blowout fracture

The temporomandibular (TMJ) joints are classified as:

Bicondylar

Plane (gliding)

What is the CR angle and direction for the PA axial (Caldwell) projection of the cranium?

15 degrees caudad

Which cranial baseline is positioned perpendicular to the IR for a lateral projection of the cranium?

Interpupillary Line (IPL)

If the IOML is positioned perpendicular to the IR for an AP axial (Towne) projection of the cranium, what is the CR orientation and direction?

37 degrees caudal

Which two facial bones are not paired?

Vomer

Mandible

What facial bone forms 3/4ths of the roof of the mouth?

Maxillary bones

Which two facial bones contain alveolar processes?

Maxillary bones

Mandible

The vertical portions of what facial bone extends upward between the maxillae and pterygoid process of the sphenoid in the posterior nasal cavity?

Palatine bone

What is the small, U-shaped bone situated at the base of the tongue?

Hyoid bone

What is the anterior process located superior to the mandibular ramus?

Coronoid process

What are the two smallest bones of the skull called that are located in the anterior part of the medial wall of the orbits, between the labyrinth of the ethmoid and the maxilla?

Lacrimal bones

What facial bone forms part of the lateral walls and the majority of the floor of the nasal cavity?

Maxillary bone

What long, narrow, and thin bones extend diagonally and inferiorly from the lateral walls of the nasal cavity (lower third)?

Inferior nasal conchae

What is the thin plate of bone situated along the MSP of the floor of the nasal cavity?

Vomer

What is the only bone that does not articulate with another bone?

Hyoid bone

Which facial bone does the tear duct pass through?

Lacrimal

What is formed by the union of the temporal process of the zygoma and the zygomatic process of the temporal bone?

Zygomatic arch

What facial bone is considered the superior tip of the vertical plates that assist in forming the posterior medial orbit?

Palatine bone

Which sinuses are the largest and most symmetric?

Maxillary sinuses

What are the essential projections for sinuses?

Right Lateral

Left Lateral

Parietoacanthial (Water’s)

What is the only projection that will demonstrate all four sinuses?

Lateral

What are the two most important considerations when imaging for sinuses?

CR horizontal (no angle)

Upright position of patient (demonstrates air fluid levels)

Which sinuses are located directly inferior to the sella turcica?

Sphenoidal sinuses

Which sinuses are occasionally absent?

Frontal sinuses

What bony structure must be projected below the maxillary sinuses for the parietoacanthial (Water’s) projection of the sinuses?

Petrous ridges

How many bones make up the cranium?

8

How many facial bones are there in total?

14

A structure found in the middle of the sphenoid bone that surrounds the pituitary gland is the:

Sella turcica

Which structure of the sphenoid bone allows for the passage of the optic nerve and is the actual opening into the orbit?

Optic foramen

What term describes the superior rim of the orbit?

Supraorbital margin

Which of the following is not part of the floor of the cranium?

1) Temporal

2) Ethmoid

3) Occipital

4) Sphenoid

3) Occipital

Which aspect of the frontal bone is thin-walled and forms the forehead?

Squamous portion

Which structures are found at the widest aspect of the skull?

Parietal tubercles

What is the thickest and densest structure in the cranium?

Petrous portion

(T/F) The sphenoid bone articulates with all the other cranial bones.

True

Which small section of bone is located superior to the cribriform plate?

Crista galli

What are the small, irregular bones found in the adult skull sutures?

Wormian

Which landmark corresponds to the highest level of petrous ridges?

TEA

What is defined as the small cartilaginous flap that covers the opening of the ear?

Tragus

There is a difference of how many degrees between the OML and IOML positioning lines?

7-8 degrees

Which projection of the cranium projects the dorsum sellae within the foramen magnum?

AP axial (Towne method)

How much central ray angle is required for the AP axial projection (Towne method) for a skull with the IOML perpendicular to the IR?

37 degrees caudad

How much central ray angle is required for the AP axial projection (Towne method) for a skull with the OML perpendicular to the IR?

30 degrees caudad

Where is the central ray centered for a lateral projection of the cranium?

2 inches superior to the EAM

To prevent tilting of the skull for the lateral projection of the cranium, the ___ line is placed perpendicular to the IR?

IPL

Where is the central ray centered for an SMV projection of the skull?

1½ inferior to the mandibular symphysis

Which positioning line is parallel to the IR for the SMV projection of the skull?

IOML

The majority of the hard palate is formed by the?

Palatine bone

Which projection of the facial bones best visualizes the region of the maxilla and orbits?

Parietoacanthial projection (Water’s)

On average, how many separate cavities make up the frontal sinus?

2

Which plane is placed parallel to the IR with a true lateral projection of the facial bones?

MSP

What is the angle between the OML and plane of the IR with a parietoacanthial projection (Water’s method)?

37 degrees

The CR is centered to exit at the level of what cranial landmark for a well-positioned parietoacanthial (Water’s) projection?

Acanthion

The CR is centered to exit at the level of which cranial landmark for a well-positioned PA axial projection of the facial bones?

Nasion

Where are the petrous ridges projected for a properly positioned parietoacanthial projection?

Lower ½ of the maxillary sinuses

Where is the CR centered for a lateral projection of the nasal bones?

½ inch inferior to nasion

If the patient cannot flex their head to place OML perpendicular to the IR for the AP axial Towne’s; what can be done to compensate for this?

IOML perpendicular

Increase CR angulation by 7 degrees caudad

If the patient cannot extend their head for an SMV projection, what can the technologist do to produce a diagnostic image?

Angle the CR to place it perpendicular to the IOML

A radiograph of a lateral projection of the cranium reveals that the orbital roofs are not superimposed. What positioning error is present?

Tilt

(T/F) The lateral projection of the nasal bones is a unilateral projection (both right and left lateral projections are not required.

False

The modified parietoacanthial (Water’s) projection requires (more/less) extension of the head and neck.

Less

The pituitary gland is associated with and protected by what bone?

Sphenoid

The point of union between the two halves of the mandible is termed?

Symphysis menti

The posterior aspect of the orbit is termed?

Apex

Upper and lower teeth are embedded in what?

Alveolar processes T

The widest portion of the cranium is found at the level of?

Parietal tubercles

What is the angle between the MSP and the IR for a parieto-orbital projection of the optic foramen?

53 degrees

What is the only paranasal sinus not contained within a cranial bone?

Maxillary

Where does the CR exit for a modified parietoacanthial (Water’s) projection of the facial bones?

Acanthion

Where is the CR centered for a lateral projection of the facial bones?

At the zygoma and between the EAM and outer canthus

Which of the following bones is involved with a tripod fracture?

1) Maxilla

2) Temporal

3) Zygomatic

4) Ethmoid

3) Zygomatic

Which cranial bone contains the cribiform plate?

Ethmoid

Which cranial bone possesses the zygomatic process?

Temporal

Which division of the temporal bone contains the organs of hearing and equilibrium?

Petrous portion

Which facial bone forms the majority of the hard palate?

Maxilla

Which of the following bones is part of the floor of the cranium?

1) Temporal

2) Frontal

3) Occipital

4) Parietal

1) Temporal

Which of the following is not true about the oblique inferiorsuperior (tangential) projection of the zygomatic arches?

1) Requires rotation and tilt of the skull to visualize

2) Small focal spot

3) No AEC

4) Grid

4) Grid

Which projection will best demonstrate the bony nasal septum?

Parietoacanthial

What structures found in the nasal cavity are described as scroll-like projections?

Conchae

Which suture separates the parietal bone from the occipital bone?

Lambdoidal

What term describes the anterior fontanel found in the adult skull?

Bregma

What cranial landmark describes the junction of the two nasal bones?

Nasion

What positioning line is placed perpendicular to the plane of the IR for a lateral nasal bone projection?

IPL

Which positioning line is perpendicular to the IR for the AP axial (Towne) projection with a 37 degree caudad CR angle?

IOML

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

1 inch posterior to outer canthus

How many bones are contained in the adult skull?

22

(8 Cranial + 14 Facial)

The base of the anterior portion of the occipital bone contains two large openings called:

Jugular foramina

The bones of the cranium are joined together by fibrous joints called:

Sutures

What is the correct respiration phase for all projections of the facial bones and sinuses?

Suspended respiration

Which of the following projections best demonstrate the condyle and neck of the mandible?

1) AP axial

2) Axiolateral

3) Axiolateral oblique

4) Verticosubmental

3) Axiolateral oblique

Which skull type is narrow from side to side?

Doliocephalic