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skull posit comp
skull positioning for comp
Question | Answer |
---|---|
Lateral skull positioning | MSP parallel, IOML parallel to long axis of IR, IPL perpendicular to IR. |
CR entry lateral skull | 2” superior to the EAM |
Eval criteria lateral skull | cranium without rotation or tilt, sella turcica in profile, superimposed orbital roofs, greater wings of sphenoid, EAM and TMJ |
PA axial skull alternate name | Caldwell |
Caldwell for skull positioning | MSP centered, pt forehead and nose touch bucky, OML perpendicular |
CR entry for Caldwell skull | 15 degrees caudad exiting the nasion |
CR entry for Caldwell skull for frontal bone | CR perpendicular |
CR entry for Caldwell skull for superior orbital fissures | CR 20-25 degrees caudad |
CR entry for Caldwell skull for rotundrum foramina | CR 25-30 degrees caudad |
Eval for Caldwell skull | symmetric petrous ridges, no tilt or rotation, petrous ridges lie in the lower 1/3 of the orbits (w/ angle), petrous ridges fill the orbits (no angle) |
AP axial skull alternate name | Towne |
Towne skull positioning | TOF at cranial vertex, OML perpendicular to IR or IOML perpendicular (changes tube angle) |
CR entry Towne for skull | CR enters 2 ½” above glabella, angle 30 degrees caudad when OML perp. Angle 37 degrees when IOML perp. |
Eval criteria Towne for skull | no rotation or tilt, symmetric petrous ridges, dorsum sellae and posterior clinoid process seen through foramen magnum. |
What piece of anatomy is used to determine rotation on a Towne skull? | foramen magnum |
A Towne for skull is done to view: | the occipital bone |
The Caldwell for skull is done to view: | the frontal bone |
SMV for skull positioning | vertex touches bucky, MSP perpendicular, IOML parallel to IR |
SMV for skull CR entry | perpendicular to IOML, midway between the mandibular angles ¾” anterior to the level of the EAM |