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Published on 03/05/2015 by admin Filed under Radiology Last modified 03/05/2015 Print this page Average : Your rating: none, Average: 5 (1 votes) Rate it This article have been viewed 9064 times 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 critiqueTrauma (Skull Series) Lateral trauma (S) AP 0°, AP 15°, and AP axial trauma (S) Lateral trauma critique AP (0° and 15°) trauma critiqueFacial Bones Lateral (R) Lateral critique Parietoacanthial (Waters and modified Waters) (R) Parietoacanthial critique PA 15° Caldwell (R) PA axial 15° Caldwell critiqueTrauma (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) critiqueParanasal Sinuses (R) Routine, (S) Special Cranial landmarks and positioning lines used in skull and facial bones positioning. Fig. 8-1Positioning 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. 8-2Cranial landmarks. AP (PA) Axial Skull*AP Towne (or PA Haas Method) • 24 × 30 cm L.W. (10 × 12″) • Grid PositionFig. 8-3AP axial (Towne)—CR 30° caudad to OML. • Seated erect, or supine, midsagittal plane aligned to CR and centerline, perpendicular to IR; no rotation or tilt • Depress chin to bring OML or IOML perpendicular to IR. • Center IR to projecting CR. Fig. 8-4PA axial (Haas method), OML ⊥ CR 25° cephalad, through level of EAMs. Central Ray:• CR 30° caudal to OML; or 37° caudal to IOML • CR to ≈2.5″ or 6 cm above glabella (through 2 cm or 0.75″ superior to level of EAMs) SID:40-44″ (102-113 cm) Collimation:On four sides to skull margins Respiration:Suspend during exposure. Note:PA Haas (p. 436 in text) is an alternate to AP Towne. Adjust head to bring OML ⊥ to IR. AP Axial(Modified Towne Method) Evaluation CriteriaAnatomy 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. 8-5AP axial skull. Lateral Skull*• 24 × 30 cm C.W. (10 × 12″) • Grid Fig. 8-6Lateral 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 SkullEvaluation CriteriaAnatomy Demonstrated:• Superimposed cranial halves • Entire sella turcica and dorsum sellae Fig. 8-7Lateral 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. 8-8PA—0°. Fig. 8-9PA 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 CriteriaAnatomy 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. 8-10PA—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. 8-11PA axial—15° Caldwell. Submentovertex (SMV) Skull*• 24 × 30 cm L.W. (10 × 12″) • Grid • AEC optional Fig. 8-12SMV—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) SkullEvaluation CriteriaAnatomy 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. 8-14Lateral, 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. 8-15AP—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. 8-16AP reverse Caldwell. CR—15° cephalad to OML—centered to nasion Fig. 8-17AP axial (Towne). CR—30° caudad to OML—centered to midpoint between EAMs Lateral Trauma SkullEvaluation CriteriaAnatomy 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. 8-18Lateral trauma skull. Trauma AP (0°) and AP Axial (15° Cephalad) ProjectionsFig. 8-19AP—0° to
OML. Fig. 8-20AP axial (“reverse” Caldwell) (15°
cephalad). Evaluation CriteriaAnatomy 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*Buy Membership for Radiology Category to continue reading. Learn more here You may also need
RelatedBontragers Handbook of Radiographic Positioning and Techniques Which projection of the skull demonstrates the petrous ridges in the lower third of the orbits?A radiograph of a PA axial (Caldwell method) projection of the cranium reveals that the petrous ridges are located at the level of the lower one third of the orbits.
Which projection of the cranium best demonstrates the frontal bone?Skull PA Occipito-Frontal
This projection demonstrates the frontal bone, crista galli, internal auditory canals, anterior ethmoid and frontal sinuses, greater and lesser wings of the sphenoid, and petrous ridges. Position of patient Prone with the vertical beam angled at 20 degrees.
Which landmark corresponds with the level of the petrous ridge?The upper border of the petrous portion is commonly referred to as the petrous ridge. The top of the ridge lies approximately at the level of an external radiography landmark called the top of ear attachment (TEA).
Where are the petrous ridges seen on a Parietoacanthial projection?skull/facial bones/sinuses/mandible/. Which of the following projections best demonstrate the petrous portion of the temporal bone?study for review class. What is Caldwell projection?The Caldwell view is a caudally angled radiograph, with its posteroanterior projection allowing for minimal radiation to the orbits. This view may be used in imaging of the skull or facial bones depending on the clinical indications.
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