The skull consists of 22 bones: 14 facial bones Caldwell's Method
etc. Registered Radiologic Technologist, Medical Student The skull consists of 22 bones: 14 facial bones Caldwell's Method etc. 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 9406 times Chapter 8 Skull, Facial Bones, and Paranasal Sinuses• Cranial positioning lines Cranium (Skull Series)  Trauma (Skull Series) Facial Bones Trauma (Facial Bone Series) Optic Foramina Zygomatic Arches Nasal Bones Mandible Temporomandibular Joints Paranasal 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 facial bones are demonstrated on the PA axial projection Caldwell method?Skull PA Axial Caldwell Method
This projection demonstrates skull fractures with medial and lateral displacement. Structures shown include the greater and lesser sphenoid wings, superior orbital fissures, frontal bone, anterior ethmoid and frontal sinuses, superior orbital margins, and crista galli.
What is the proper centering point for PA projection of the sinuses?Centering point: 2 cm posterior to the outer canthus.
What angle of the CR is used for a PA axial Caldwell view of the facial bones?What is the central ray for the PA (exaggerated Caldwell) projection for facial bones? CR angled 30° caudal, exiting nasion to 1/2 inch below nasion to MOF & DLA.
When taking a PA axial projection Caldwell method of the skull the central ray is?When taking a PA axial projection (Caldwell method) of the skull, the central ray is directed: Angled 15 degrees caudad to center of IR through Nasion.
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When positioning for a PA Caldwell for facial bones the midsagittal plane is?
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