Skull, Facial Bones, and Paranasal Sinuses

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Chapter 8

Skull, Facial Bones, and Paranasal Sinuses

• Cranial positioning lines

Cranium (Skull Series)

AP axial (Towne method) and PA axial (Haas method) (R)

AP axial critique

Lateral (R)

Lateral critique

PA (0°) and PA (15° or 23°) Caldwell (R)

PA Caldwell critique

Submentovertex (SMV) (S)

SMV critique

Trauma (Skull Series)

Lateral trauma (S)

AP 0°, AP 15°, and AP axial trauma (S)

Lateral trauma critique

AP (0° and 15°) trauma critique

Facial Bones

Lateral (R)

Lateral critique

Parietoacanthial (Waters and modified Waters) (R)

Parietoacanthial critique

PA 15° Caldwell (R)

PA axial 15° Caldwell critique

Trauma (Facial Bone Series)

Lateral, acanthioparietal (reverse Waters and modified Waters) (S)

Optic Foramina

Parieto-orbital oblique (Rhese method) (S)

Zygomatic Arches

Submentovertex (SMV) (R)

Tangential (R)

SMV and tangential critique

AP axial (modified Towne) (S)

Nasal Bones

Lateral (R)

Lateral critique

Superoinferior (axial) (S)

Mandible

PA and PA axial (R)

Axiolateral oblique (R)

Trauma axiolateral oblique (S)

PA and axiolateral oblique critique

AP axial (mandible or TMJ) (R)

Temporomandibular Joints

Axiolateral oblique (Law) (S)

Axiolateral (Schuller) (S)

Axiolateral (Law and Schuller) critique

Paranasal Sinuses

Lateral (R)

PA (Caldwell) (R)

Lateral and PA (Caldwell) critique

Parietoacanthial (Waters) (R)

Submentovertex (SMV) (S)

Waters and SMV critique

(R) Routine, (S) Special

Cranial landmarks and positioning lines used in skull and facial bones positioning.

Fig. 8-1 Positioning lines.

A Glabellomeatal line (GML)

B Orbitomeatal line (OML)

C Infraorbitomeatal line (IOML) (Reid’s base line, or “base line,” base of cranium)

D Acanthiomeatal line (AML)

E Lips-meatal line (LML) (used for modified Waters)

F Mentomeatal line (MML) (used for Waters)

Fig. 8-2 Cranial landmarks.

AP (PA) Axial Skull ^*

AP Towne (or PA Haas Method)

• 24 × 30 cm L.W. (10 × 12″)

• Grid

AP Axial

(Modified Towne Method)

Evaluation Criteria

Anatomy Demonstrated:

• Occipital bone, petrous pyramids, and foramen magnum

Position:

• Dorsum sellae within foramen magnum

• No rotation evident by symmetry of petrous pyramids

Exposure:

• Optimal density (brightness) and contrast to visualize occipital bone

• Sharp bony margins; no motion

Fig. 8-5 AP axial skull.

Lateral Skull ^*

• 24 × 30 cm C.W. (10 × 12″)

• Grid

Fig. 8-6 Lateral skull.

Position

• Seated erect or semiprone on table

• No rotation or tilt, midsagittal plane parallel to IR, and IPL perpendicular to IR

• Adjust chin to place IOML parallel to upper and lower IR edges

• Center IR to CR.

Central Ray:

CR ⊥ to IR, ≈2″ (5 cm) superior to EAM

SID:

40-44″ (102-113 cm)

Collimation:

On four sides to skull margins

Respiration:

Suspend during exposure.

Lateral Skull

Evaluation Criteria

Anatomy Demonstrated:

• Superimposed cranial halves

• Entire sella turcica and dorsum sellae

Fig. 8-7 Lateral skull.

Position:

• No tilt, evident by superimposition of orbital plates (roofs)

• No rotation, evident by superimposition of greater wings of sphenoid and mandibular rami

Exposure:

• Optimal density (brightness) and contrast to visualize sellar structures

• Sharp bony margins; no motion

PA (0° and 15°) Caldwell Skull ^*

Note: Some departmental routines include a 0° PA to better demonstrate the frontal bone in addition to the 15° PA axial Caldwell.

• 24 × 30 cm L.W. (10 × 12″)

• Grid

Position

• Seated erect, or prone on table, head aligned to CR and centerline of IR

• With forehead and nose resting on tabletop, adjust head to place OML perpendicular to IR.

• No rotation or tilt, midsagittal plane perpendicular to IR

• Center IR to projected CR.

Fig. 8-8 PA—0°.

Fig. 8-9 PA axial—15° Caldwell.

Central Ray:

• PA 0°: CR ⊥ to IR, centered to exit at glabella

• PA axial (Caldwell): CR 15° caudad to OML, centered to exit at nasion (25°–30° best demonstrates orbital margins)

SID:

40-44″ (102-113 cm)

Collimation:

On four sides to skull margins

Respiration:

Suspend during exposure.

PA (0°) and PA Axial Caldwell (15° Caudad)

Evaluation Criteria

Anatomy Demonstrated:

• PA 0°: Frontal bone and crista galli demonstrated without distortion

• PA axial 15°: Greater/lesser wings of sphenoid, frontal bone, and superior orbital fissures

Fig. 8-10 PA—0°.

Position:

• PA 0°: Petrous ridges at level of superior orbital margin. No rotation; equal distance between orbits and lateral skull

• PA axial 15°: Petrous ridges projected in lower ⅓ of orbits. No rotation; equal distance between orbits and lateral skull

Exposure:

• Optimal density (brightness) and contrast to visualize frontal bone and surrounding structures

• Sharp bony margins; no motion

Fig. 8-11 PA axial—15° Caldwell.

Submentovertex (SMV) Skull ^*

• 24 × 30 cm L.W. (10 × 12″)

• Grid

• AEC optional

Fig. 8-12 SMV—CR ⊥ to IOML.

Position

• Seated erect or supine with head extended over end of table resting top of head against grid IR (may tilt table up slightly)

• Adjust IR and head to place IOML parallel to IR.

• Ensure no rotation or tilt.

• Center IR to CR.

Central Ray:

CR angled to be ⊥ to IOML, centered to 0.75″ (2 cm) anterior to level of EAMs (midpoint between angles of mandible)

Note:

If patient cannot extend head this far, adjust CR as needed to remain perpendicular to IOML.

SID:

40-44″ (102-113 cm)

Collimation:

On four sides to skull margins

Respiration:

Suspend during exposure.

Submentovertex (SMV) Skull

Evaluation Criteria

Anatomy Demonstrated:

• Base of skull, including mandible and occipital bone

• Foramen ovale and spinosum

Position:

• Mandibular condyles are anterior to the petrous bones

• No tilt; equal distance between mandibular condyles and lateral skull

• No rotation; MSP parallel to edge of radiograph

Fig. 8-13 SMV.

Exposure:

• Optimal density and contrast (brightness) to visualize outline of foramen magnum

• Sharp bony margins; no motion

Lateral Trauma Skull ^*

Warning: Do NOT elevate or move patient’s head before cervical spine injuries have been ruled out.

• 24 × 30 cm C.W. (10 × 12″)

• Grid

Fig. 8-14 Lateral, with possible spinal injury.

Position

• Supine, without removing cervical collar if present

• With possible spinal injury, move patient to back edge of table and place IR about 1″ (2.5 cm) below tabletop and posterior skull (move floating tabletop forward).

• Center IR to horizontal beam CR (to include entire skull).

• Ensure no rotation or tilt.

Central Ray:

CR horizontal, ⊥ to IR, centered to ≈2″ (5 cm) superior to EAM

SID:

40-44″ (102-113 cm)

Collimation:

On four sides to skull margins

Respiration:

Suspend respiration.

AP Trauma Skull Series ^*

Warning: With possible spine or severe head injuries, take all projections AP without moving head or without removing cervical collar if present.

• 24 × 30 cm L.W. (10 × 12″)

• Grid (Bucky)

Fig. 8-15 AP—0° to OML.CR—parallel to OML—centered to glabella

Position

• Patient carefully moved onto x-ray table in supine position

• All projections taken as is without moving head

SID:

40-44″ (102-113 cm)

Collimation:

On four sides to skull margins

Respiration:

Suspend during exposure, or take “as is.”

CR Angle and Centering

• As indicated under each photo

• IR centered to projected CR

Fig. 8-16 AP reverse Caldwell. CR—15° cephalad to OML—centered to nasion

Fig. 8-17 AP axial (Towne). CR—30° caudad to OML—centered to midpoint between EAMs

Lateral Trauma Skull

Evaluation Criteria

Anatomy Demonstrated:

• Superimposed cranial halves

• Entire sella turcica and dorsum sellae

Position:

• No rotation or tilt (see p. 229 for specific criteria)

Exposure:

• Optimal density (brightness) and contrast to visualize sellar structures

• Sharp bony margins; no motion

Fig. 8-18 Lateral trauma skull.

Trauma AP (0°) and AP Axial (15° Cephalad) Projections

Fig. 8-19 AP—0° to OML.

Fig. 8-20 AP axial (“reverse” Caldwell) (15° cephalad).

Evaluation Criteria

Anatomy Demonstrated:

• AP 0°: Frontal bone and crista galli demonstrated (magnified because of OID)

• AP axial 15°: Greater/lesser wings of sphenoid, frontal bone, and superior orbital fissures (magnified)

Position:

• AP 0°: Petrous ridges at level of superior orbital margin. No rotation; equal distance between orbits and lateral skull

• AP axial 15°: Petrous ridges projected in lower ⅓ of orbits. No rotation; equal distance between orbits and lateral skull

Exposure:

• Optimal density (brightness) and contrast to visualize frontal bone and surrounding structures

• Sharp bony margins; no motion

Facial Bones—Lateral ^*

• 8 × 10″ L.W. (18 × 24 cm)

• Grid

Fig. 8-21 Lateral facial bones.

Position

• Seated erect or semiprone on table

• No rotation or tilt, midsagittal plane parallel to IR, IPL perpendicular to IR

• Adjust chin to place IOML parallel to top and bottom edge of IR.

• Center IR to CR.

Central Ray:

CR ⊥ to IR, centered to midway between EAM and outer canthus

SID:

40-44″ (102-113 cm)

Collimation:

On four sides to area of facial bones

Respiration:

Suspend during exposure.

Lateral Facial Bones

Evaluation Criteria

Anatomy Demonstrated:

• Superimposed facial bones, greater wings of sphenoid and sella turcica

• Region from orbital roofs to mentum demonstrated

Position:

• No tilt; evident by superimposition of orbital plates (roofs)

• No rotation; evident by superimposition of greater wings of sphenoid and mandibular rami

Fig. 8-22 Lateral facial bones.

Exposure:

• Optimal density (brightness) and contrast to visualize facial structures

• Sharp bony margins; no motion

Facial Bones—Parietoacanthial ^*

(Waters and Modified Waters)

• 24 × 30 cm L.W. (10 × 12″) or 18 × 24 cm L.W. (8 × 10″)

• Grid

Fig. 8-23 PA Waters, OML 37°—CR and MML ⊥.

Fig. 8-24 PA modified Waters, OML 55°—CR and LML ⊥.

Position

Waters:

• Seated erect or prone on table

• Extend head resting on chin; place MML ⊥ to IR, which places the OML 37° to IR.

• Center IR to CR.

Modified Waters:

• OML is 55° to the plane of the IR, or line from junction of lips to EAM (LML) is ⊥ to IR.

Central Ray:

CR ⊥ to IR, to exit at acanthion (both projections)

SID:

40-44″ (102-113 cm)

Collimation:

On four sides to area of facial bones

Respiration:

Suspend during exposure.

Parietoacanthial and Modified Parietoacanthial

Fig. 8-25 PA Waters.

Fig. 8-26 PA modified Waters.

(Waters and Modified Waters)

Evaluation Criteria

Anatomy Demonstrated:

• Waters: Inferior orbital rims, maxillae, and nasal septum

• Modified Waters: Inferior orbital floors in profile (undistorted)

Position:

• Waters: Petrous ridges just inferior to floor of maxillary sinuses. No rotation; equal distance between orbits and lateral skull

• Modified Waters: Petrous ridges projected in lower ½ of maxillary sinuses. No rotation; equal distance between orbits and lateral skull

Exposure:

• Optimal density (brightness) and contrast to visualize maxillary region and surrounding structures

• Sharp bony margins; no motion

Facial Bones—PA Axial (Caldwell)^*

• 24 × 30 cm L.W. (10 × 12″) or 18 × 24 cm L.W. (8 × 10″)

• Grid

Fig. 8-27 PA axial—15° Caldwell (OML ⊥); CR to exit at nasion.

Position

• Seated erect or prone on table, MSP aligned to CR and to centerline of IR

• With forehead and nose resting on tabletop, adjust head to place OML perpendicular to IR; ensure no rotation or tilt.

• Center IR to projected CR (to nasion).

Central Ray:

CR 15° caudal to OML, centered to exit at nasion

Note:

A 30° CR angle is required to project lower orbits below petrous ridges if this is an area of interest.

SID:

40-44″ (102-113 cm)

Collimation:

On four sides to skull (facial bones) margins

Respiration:

Suspend during exposure.

PA Axial (15° Caudad) Caldwell

Evaluation Criteria

Anatomy Demonstrated:

• PA axial 15°: Orbital rims, maxillae, nasal septum, and zygomatic arches

Position:

• PA axial 15°: Petrous ridges projected in lower ⅓ of orbits. No rotation; equal distance between orbits and lateral skull margins

Exposure:

• Optimal density (brightness) and contrast to visualize maxillary region and orbital floor

• Sharp bony margins; no motion

Fig. 8-28 PA axial Caldwell—15° caudad.

Facial Bones—Trauma Series ^*

Warning: With possible spine or severe head injuries, take all projections supine without moving head or without removing cervical collar if present.

Lateral (Horizontal Beam)

• 18 × 24 cm L.W. (8 × 10″)

• Grid, placed on edge against lateral cranium

• Ensure no rotation or tilt, MSP parallel to IR

• CR horizontal, to midway between outer canthus and EAM

Reverse Waters

• 18 × 24 cm L.W. (8 × 10″)

• Grid (Bucky), AEC—center field

• MSP aligned to CR and centerline of table or IR

• Ensure no rotation or tilt.

• CR parallel to MML

• CR centered to acanthion (CR angled cephalad as needed unless head can be tilted back if cervical injury has been ruled out).

Reverse Modified Waters

• Same as reverse Waters except:

• CR parallel to junction of lips-meatal line (LML), which is 18°–20° from MML

• CR centered to acanthion

Fig. 8-29 Horizontal beam lateral—CR to midway between outer canthus and EAM.

Fig. 8-30 Trauma reverse Waters—CR parallel to MML, centered to acanthion.

Fig. 8-31 Trauma reverse modified Waters—CR parallel to LML, centered to acanthion.

Optic Foramina—Parieto-orbital Oblique ^*

(Rhese Method)

• 18 × 24 cm C.W. (8 × 10″)

• Grid

• R and L sides taken for comparison

• AEC not recommended because of small body part

Position

• Seated erect or prone on table

• As a starting reference, adjust the head so the nose, cheek, and chin are touching the tabletop.

• Adjust the head so the AML is perpendicular to the IR, and the midsagittal plane is 53° to the IR (use angle indicator).

• Center IR to CR (to downside orbit).

Fig. 8-32 A, Rhese oblique (right side). B, Rhese oblique. —.AML and CR ⊥ — 53° rotation of head from lateral

Central Ray:

CR ⊥ to IR, to center of downside orbit

SID:

40-44″ (102-113 cm)

Collimation:

Closely collimate to 3-4″ (8-10 cm) square.

Respiration:

Suspend during exposure.

Zygomatic Arches—Bilateral ^*

Submentovertex (SMV) Projection

• 18 × 24 cm C.W. (8 × 10″)

• Nongrid or grid

• No AEC

Fig. 8-33 SMV, bilateral zygomatic arches, erect—CR ⊥ to IOML (nongrid may be preferred).

Position

• Seated erect or supine with head extended over end of table resting top of head against grid IR (may tilt table up slightly)

• Adjust IR and head to place IOML parallel to IR.

• Ensure no rotation or tilt.

• Center IR to CR.

Central Ray:

CR angled as needed to be ⊥ to IOML, centered to midway between zygomatic arches (≈1.5″ or 4 cm inferior to mandibular symphysis)

SID:

40-44″ (102-113 cm)

Collimation:

To include area of zygomatic arches

Respiration:

Suspend during exposure.

Zygomatic Arches—Tangential ^*

(Oblique Inferosuperior Projection)

Bilateral arches generally taken for comparison.

• 18 × 24 cm C.W. (8 × 10″)

• Nongrid or grid

• AEC not recommended

Fig. 8-34 Tangential of left zygomatic arch—CR ⊥ to IOML, head tilted 15°, rotated 15°.

Position

• Position as for an SMV skull with the IOML parallel to the IR.

• Rotate the head ≈15° toward side being examined.

• Tilt the midsagittal plane with the chin toward the side of interest about 15° or as needed to free the zygomatic arch from superimposition by mandible or parietal bone.

• Center IR to CR.

Central Ray:

CR angled if needed to be ⊥ to IOML, centered to mid-zygomatic arch

SID:

40-44″ (102-113 cm)

Collimation:

Collimate closely to area of interest.

Respiration:

Suspend during exposure.

Submentovertex (SMV) and Oblique Tangential Zygomatic Arches

Fig. 8-35 SMV.

Fig. 8-36 Oblique tangential.

Evaluation Criteria

Anatomy Demonstrated:

• SMV: Bilateral zygomatic arches

• Tangential: Unilateral zygomatic arch

Position:

• SMV: Unobstructed view of bilateral arches. No rotation; symmetry of arches.

• Oblique tangential: Unilateral view of unobstructed arch. No superimposition of arch with parietal bone or mandible

Exposure:

• Optimal density (brightness) and contrast to visualize the zygomatic arches

• Sharp bony margins with soft tissue detail; no motion

Bilateral Zygomatic Arches—AP Axial ^*

(Modified Towne)

• 18 × 24 cm C.W. (8 × 10″)

• Grid

• AEC not recommended

Position

• Seated erect or supine on table, midsagittal plane aligned to midline of table or IR; ensure no rotation or tilt

• Depress chin to bring either the OML or the IOML perpendicular to IR.

• Center IR to projected CR.

Fig. 8-37 A, AP axial—CR 37° to IOML. B, AP axial.

Central Ray:

• CR 30° caudal to OML; or 37° to IOML

• CR 1″ (2.5 cm) superior to glabella to pass through level of midarches

SID:

40-44″ (102-113 cm)

Collimation:

On four sides to area of bilateral arches

Respiration:

Suspend during exposure.

Nasal Bones—Lateral ^*

Bilateral projections generally taken for comparison.

• 18 × 24 cm C.W. (8 × 10″) (bilateral/divided on same IR)

• Nongrid—detail screens

Fig. 8-38 Right lateral—nasal bones.

Position

• Seated erect or semiprone on table

• Center nasal bones to half of IR and to CR.

• Adjust head to bring IOML parallel to top and bottom edge of IR.

• Ensure a true lateral, IPL perpendicular to IR, and midsagittal plane parallel to IR.

Central Ray:

CR ⊥ to IR, centered to ≈0.5″(1.25 cm) inferior to nasion

SID:

40-44″ (102-113 cm)

Collimation:

Closely collimate to ≈4″ (10 cm) square.

Respiration:

Suspend during exposure.

Lateral Nasal Bones

Fig. 8-39 Lateral nasal bones.

Evaluation Criteria

Anatomy Demonstrated:

• Nasal bones with soft tissue structures

• Frontonasal suture to anterior nasal spine

Position:

• No rotation; complete profile of nasal bones

• Frontonasal suture to anterior nasal spine within collimation field

Exposure:

• Optimal density (brightness) and contrast to visualize nasal bones and surrounding soft tissue structures

• Sharp bony margins with soft tissue detail; no motion

Nasal Bones ^*

Superoinferior Axial (Tangential) Projection

• 18 × 24 cm C.W. (8 × 10″)

• Nongrid—detail screens

Fig. 8-40 Seated.

Position

• Seated erect at end of table or prone on table

• If prone, place supports under chest and under IR.

• Rest extended chin on IR, which should be perpendicular to GAL (glabelloalveolar line) and to CR.

Central Ray:

CR directed parallel to GAL, centered to nasion

SID:

40-44″ (102-113 cm)

Collimation:

Closely collimate to ≈4″ (10 cm) square.

Respiration:

Suspend during exposure.

Fig. 8-41 Superoinferior.

Mandible—PA and PA Axial ^*

• 18 × 24 cm L.W. (8 × 10″)

• Grid

• AEC not recommended

Fig. 8-42 PA mandible—CR and OML ⊥ to IR.)

Position

• Seated erect or prone on table, head aligned to centerline

• With forehead and nose resting on tabletop, adjust head to place OML ⊥ to IR.

• No rotation or tilt, midsagittal plane ⊥ to IR

• Center IR to CR (level of junction of lips).

Central Ray:

CR ⊥ to IR, to exit at level of lips

Note:

A CR angle of 20°–25° cephalad centered to exit at the acanthion best demonstrates proximal rami and condyles.

SID:

40-44″ (102-113 cm)

Collimation:

Collimate to area of mandible (square area).

Respiration:

Suspend during exposure.

Mandible—Axiolateral Obliques ^*

R and L sides generally taken for comparison unless contraindicated.

• 18 × 24 cm C.W. (8 × 10″)

• Grid or nongrid

Fig. 8-43 Semisupine.

Fig. 8-44 Erect.

— CR 25° cephalad

— 10°–15° head rotation for general survey (as shown above)

— 0° head rotation for ramus

— 30° head rotation for body

— 45° head rotation for mentum

Position

• Seated erect, semiprone, or semisupine, with support under shoulder and hip

• Extend chin, with side of interest against IR.

• Adjust head so IPL is perpendicular to IR, no tilt.

• Rotate head toward IR as determined by area of interest.

Central Ray:

CR 25° cephalad to IPL, centered to downside midmandible (≈2″ or 5 cm below upside angle)

SID:

40-44″ (102-113 cm)

Collimation:

To area of mandible (square area)

Respiration:

Suspend during exposure.

Mandible—Trauma Axiolateral Oblique ^*

For trauma patients unable to cooperate.

• 18 × 24 cm C.W. (8 × 10″)

• Grid or nongrid

Fig. 8-45 Horizontal beam axiolateral—CR 30° cephalad from lateral, 5°–10° down.

Position

• Supine, no rotation of head, MSP ⊥ to TT

• IR on edge next to face, parallel to MSP with lower edge of IR ≈1″ (2.5 cm) below lower border of mandible

• Depress shoulders and elevate or extend chin if possible.

Note:

May rotate head toward IR slightly (10°–15°) to better visualize body or mentum of mandible if this is area of interest.

Central Ray:

• CR horizontal beam, 30° cephalad (from lateral or IPL); angled down (posteriorly) 5°–10° to clear shoulder

• CR centered to ≈2″ (5 cm) distal to angle of mandible on side away from IR

SID:

40-44″ (102-113 cm)

Collimation:

To area of mandible (square area)

Respiration:

Suspend during exposure.

PA and Axiolateral Oblique Mandible

Fig. 8-46 PA mandible.

Fig. 8-47 Axiolateral oblique mandible.

Evaluation Criteria

Anatomy Demonstrated:

• PA: Mandibular rami and lateral portion of body

• Axiolateral: Mandibular rami, condylar and coronoid processes, and body of near side

Position:

• PA: No rotation evident by symmetry of rami

• Axiolateral: Unobstructed view of mandibular rami, body, and mentum. No foreshortening of area of interest.

Exposure:

• Optimal density (brightness) and contrast to visualize mandibular area of interest

• Sharp bony margins; no motion

AP Axial Mandible ^*

(Temporomandibular Joints)

• 18 × 24 cm L.W. (8 × 10″)

• Grid

Fig. 8-48 AP axial, CR 35° to OML (CR centered for mandible).

Position

• Seated erect or supine on table, midsagittal plane centered to midline of table; ensure no rotation or tilt

• Depress chin to bring OML perpendicular to IR if possible (or bring IOML perpendicular and add 7° to CR angle).

• Center IR to projected CR.

Central Ray:

• CR 35° caudad to OML (42° to IOML)

• CR centered to glabella for mandible

Note:

CR centered ≈2″ (5 cm) above glabella to pass through TMJs if TMJs are of primary interest.

SID:

40-44″ (102-113 cm)

Collimation:

To include from TMJs to body of mandible

Respiration:

Suspend during exposure.

Temporomandibular Joints ^*

Axiolateral Oblique (Modified Law Method)

R and L sides for comparison in both open and closed mouth positions.

• 18 × 24 cm C.W. (8 × 10″)

• Grid

Fig. 8-49 Closed mouth.

Position

• Seated erect or semiprone on table, affected side down

• Adjust chin to place IOML parallel to top edge of IR.

• Anterior head (midsagittal plane) rotated 15° toward IR, no tilt, IPL remains perpendicular to IR

• Portion of IR being exposed centered to projected CR

• Second exposure in same position except with mouth fully open

Fig. 8-50 Open mouth. —15° oblique (from lateral) and 15° CR (caudad)

Central Ray:

CR 15° caudad, center to exit through downside TMJ (to enter 1.5″ or 4 cm superior to upside EAM)

SID:

40-44″ (102-113 cm)

Collimation:

Collimate to 3-4″ (8-10 cm) square.

Respiration:

Suspend during exposure.

Temporomandibular Joints ^*

Axiolateral (Schuller Method)

R and L sides for comparison in both open and closed mouth positions.

• 18 × 24 cm C.W. (8 × 10″)

• Grid

Fig. 8-51 Closed mouth.

Position

• Seated erect or semiprone, affected side down

• Adjust chin to place IOML parallel to top and bottom edges of IR, true lateral, no rotation or tilt of head.

• Portion of IR being exposed centered to projected CR

• Second exposure in same position except with mouth fully open

Fig. 8-52 Open mouth. —25° caudad, 0° rotation

Central Ray:

CR 25° caudad, center to exit through downside TMJ (to enter ≈2″ or 5 cm superior and 0.5″ or 1-2 cm anterior to upside EAM)

SID:

40-44″ (102-113 cm)

Collimation:

Collimate to 3-4″ (8-10 cm) square.

Respiration:

Suspend during exposure.

Axiolateral Oblique (Modified Law Method) and Axiolateral (Schuller method) TMJ Projections

Fig. 8-53 Axiolateral oblique—closed mouth, downside TMJ shown in fossa (modified Law).

Fig. 8-54 Axiolateral projection—open mouth; TMJ shown with condyle moved to anterior margin of fossa (Schuller).

Note:

Positioning routine would require both open and closed mouth of modified Law method, or both open and closed of Schuller method.

Evaluation Criteria

Anatomy Demonstrated:

• Modified Law: Bilateral, functional study of TMJ and fossa

• Modified Schuller: Bilateral, functional study of TMJ and fossa

Position:

• Modified Law: Unobstructed view of TMJ in both open and closed mouth positions (only closed mouth is shown)

• Schuller: Unobstructed view of TMJ in both open and closed mouth positions (only open mouth is shown)

Exposure:

• Optimal density (brightness) and contrast to visualize the TMJ and mandibular fossa

• Sharp bony margins; no motion

Lateral Paranasal Sinuses ^*

Requires an erect position with horizontal CR to demonstrate air-fluid levels.

• 18 × 24 cm L.W. (8 × 10″)

• Grid

• AEC not recommended

Fig. 8-55 Erect lateral.

Position

• Erect, seated facing IR, turn head into lateral position

• Adjust height of IR to center IR to level of EAM.

• Raise chin to bring IOML parallel to floor.

• No rotation, midsagittal plane parallel and IPL ⊥ to IR

• Center IR to CR.

Central Ray:

CR horizontal to midpoint between EAM and outer canthus

SID:

40-44″ (102-113 cm)

Collimation:

Collimate on four sides to area of sinuses.

Respiration:

Suspend during exposure.

PA Paranasal Sinuses ^*

(Caldwell Method)

Requires an erect position with horizontal CR to demonstrate air-fluid levels.

• 18 × 24 cm L.W. (8 × 10″)

• Grid

• AEC not recommended

Fig. 8-56 PA Caldwell (if IR holder can be tilted).

Fig. 8-57 Modified PA Caldwell (if IR holder cannot be tilted).

Position

PA Caldwell:

• Seated erect, facing IR, tilt top of IR 15° toward patient

• Adjust head so OML is ⊥ to IR, no rotation.

• IR centered to CR (nasion)

Modified PA Caldwell:

• Tilt head back to bring OML 15° from horizontal.

Central Ray:

CR horizontal, centered to exit at nasion

SID:

40-44″ (102-113 cm)

Collimation:

To area of sinuses

Respiration:

Suspend during exposure.

Lateral and PA Caldwell Sinuses

Fig. 8-58 Lateral sinuses.

Fig. 8-59 PA axial (Caldwell) sinuses.

Evaluation Criteria

Anatomy Demonstrated:

• Lateral: All paranasal sinuses demonstrated

• PA Caldwell: Frontal and anterior ethmoid sinuses

Position:

• Lateral: No rotation or tilt; superimposition of greater wings/sphenoid, orbital roofs, and sella turcica

• PA Caldwell: Petrous ridges in lower ⅓ of orbits. No rotation; equal distance between orbits and lateral skull

Exposure:

• Optimal density (brightness) and contrast to visualize the paranasal sinuses

• Sharp bony margins with soft tissue detail; no motion

Paranasal Sinuses ^*

Parietoacanthial (Waters Method)

Requires an erect position with horizontal CR to demonstrate air-fluid levels.

• 18 × 24 cm L.W. (8 × 10″)

• Grid

• AEC not recommended

Fig. 8-60 PA erect Waters, MML ⊥, and CR horizontal.

Position

• Seated erect, chin extended and touching IR holder

• Adjust height of IR to center IR to acanthion.

• Adjust MML perpendicular to IR (OML is 37° to IR).

• No rotation, midsagittal plane perpendicular to IR holder

• Center IR to CR.

Optional Open-Mouth Position

• Patient opens mouth wide to better visualize sphenoid sinuses through the open mouth

Central Ray:

CR horizontal and ⊥ to IR, to exit at acanthion

SID:

40-44″ (102-113 cm)

Collimation:

Collimate on four sides to area of sinuses.

Respiration:

Suspend during exposure.

Paranasal Sinuses ^*

Submentovertex (SMV)

Requires an erect position with horizontal CR to demonstrate air-fluid levels.

• 18 × 24 cm L.W. (8 × 10″)

• Grid

• AEC not recommended

Fig. 8-61 SMV sinuses—CR ⊥ to IOML and IR.

Position

• Seated erect, leaning back in chair and extending head to rest top of head against IR holder

• Adjust head to place IOML as near parallel to plane of IR as possible; ensure no rotation or tilt.

• Center IR to CR.

Central Ray:

CR horizontal and ⊥ to IOML, centered to midpoint between angles of mandible

SID:

40-44″ (102-113 cm)

Collimation:

On four sides to area of sinuses

Respiration:

Suspend during exposure.

Parietoacanthial (Waters Method) Sinuses and Submentovertex (SMV)

Fig. 8-62 PA (Waters) sinuses.

Fig. 8-63 SMV sinuses.

Evaluation Criteria

Anatomy Demonstrated:

• Waters: Unobstructed view of maxillary sinuses

• SMV: Unobstructed view of sphenoid, maxillary, and ethmoid sinuses

Position:

• Waters: Petrous ridges just inferior to floor of maxillary sinuses. No rotation; equal distance between orbits and lateral skull

• SMV: Mandibular condyles projected anterior to petrous bone. No rotation or tilt; symmetry of petrous pyramids and equal distance between mandibular border and lateral skull

Exposure:

• Optimal density (brightness) and contrast to visualize the paranasal sinuses

• Sharp bony margins with soft tissue detail; no motion

^*Bontrager Textbook, 8th ed, p. 411.

^*Bontrager Textbook, 8th ed, p. 412.

^*Bontrager Textbook, 8th ed, pp. 413 and 414.

^*Bontrager Textbook, 8th ed, p. 415.

^*Bontrager Textbook, 8th ed, p. 594.

^*Bontrager Textbook, 8th ed, p. 595.

^*Bontrager Textbook, 8th ed, p. 418.

^*Bontrager Textbook, 8th ed, pp. 419 and 421.

^*Bontrager Textbook, 8th ed, p. 420.

^*Bontrager Textbook, 8th ed, p. 597.

^*Bontrager Textbook, 8th ed, p. 427.

^*Bontrager Textbook, 8th ed, p. 424.

^*Bontrager Textbook, 8th ed, p. 425.

^*Bontrager Textbook, 8th ed, p. 426.

^*Bontrager Textbook, 8th ed, p. 422.

^*Bontrager Textbook, 8th ed, p. 423.

^*Bontrager Textbook, 8th ed, p. 429.

^*Bontrager Textbook, 8th ed, p. 428.

^*Bontrager Textbook, 8th ed, pp. 428 and 598.

^*Bontrager Textbook, 8th ed, p. 430.

^*Bontrager Textbook, 8th ed, p. 434.

^*Bontrager Textbook, 8th ed, p. 435.

^*Bontrager Textbook, 8th ed, p. 436.

^*Bontrager Textbook, 8th ed, p. 437.

^*Bontrager Textbook, 8th ed, p. 438.

^*Bontrager Textbook, 8th ed, p. 439.

Bontragers Handbook of Radiographic Positioning and Techniques

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Skull, Facial Bones, and Paranasal Sinuses

Skull, Facial Bones, and Paranasal Sinuses