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Cranium & Skull
Skull Positioning Week 3 & 4
| Question | Answer |
|---|---|
| Which specific positioning error is present if the mandibular rami ar not superimposed on a lateral skull radiograph? | Rotation |
| Which specific positioning error(s) is/are present if the Petrous Ridges are projected higher in the orbits then expected for a 15 degree axial projection. What is the positioning error if there's lack of symmetry of the Petrous ridges? | Excessive flexion at the neck, or too much angle on CR. Rotation. |
| Where will the Petrous Ridges be projected with a 15 degree PA axial (Caldwell) projection on the cranium. | In the lower 3rd of the orbits. |
| Where is the CR centered for a lateral of the Sella Turcica? What will be demonstrated to tell if I've centered the CR correctly? | 3/4" anterior & 3/4 superior to EAM. Will demonstrate the anterior & posterior Clinoid process with no divergence. |
| Which skull projection best demonstrates the Sella Turcica in profile? | Lateral skull. |
| Which imaging modality is usually performed on neonates with a possible intracranial hemmorhage? | Ultrasound |
| What are the 5 most common errors made during skull radiography? Which 2 of those are the most common? | Rotation, Tilt, Excessive Flexion, Excessive Extension, Incorrect CR angulation. Rotation & Tilt are the most common. |
| Which skull projection best demonstrates the Clivus in profile? | Lateral |
| Which focal spot is used for skull projections? | Small focal spot. |
| What is used as the primary control of rotation for a true lateral skull? What is used as 2ndry? | Aligning Mid Sagittal Plane parallel to the IR is primary. The Glabella and Inion should be equal distance to the IR. |
| What is the primary control of tilt for a lateral skull? | Aligning the Interpupillary line perpendicular to the IR is the primary. |
| What positioning lines can be used to position skull directly in the center of the IR for a lateral skull? | Aligning the IOML parallel to the transverse axis of the IR |
| What is the general centeriong point for the CR on a lateral skull? | CR centered 45 degrees anterosuperior 1" from TEA (diagonal). |
| What can be used to assess for rotation on a lateral skull radiograph? | The posterior edge of the Rt & Lt mandibular rami should be superimposed. |
| What can be used to asses for tilt on a lateral skull radiograph? | The Rt & Lt orbital plates on the horizontal portion of the frontal bone should be superimposed. If there's scissor effect, there's tilt. |
| Why must a paient be cleared from a X-table lateral C-spine prior to performing a x-table lateral skull? | Because the patient's head must be lifted up to place a sponge underneath the patient's head for the x-table lateral skull. |
| For the PA Axial (Caldwell) method, how much and which direction should the CR be angled? Where should it be centered? | CR angled 15 degrees caudad to the OML. The CR should exit at the Nasion. |
| What can be used to assess that patient is in the correct position for a PA (caldwell) Axial Skull projection? What's used to assess for rotation? | Face flat to IR with head flexed. Check that OML is perpendicular to the IR. Align MId Sagittal Plane perpendicular to IR. The Mastoid Tips should be equidistant to determine rotation. The ankles can be tugged to line the patient up. |
| What alternate projection can be used on a trauma/unconcious patient instead of a PA Axial (Caldwell) skull? How much and which direction is the CR angled? Where is it centered? | The Reverse Caldwell. AP Axial skull. The CR is angled 15 degrees cephalic to the OML and centered at the Nasion. |
| What can be assessed on the PA Axial (Caldwell) and AP Axial (Reverse Caldwell) radiograph's to be sure the patient and CR is in the correct position? What can be done to correct it? | The Petrous Pyramids should be projected into the lower 1/3 of the orbits. CR angle may be too little, or too much. Or the OML may not be truly perpendicular to the IR. |
| What is used to assess for rotation on the PA Axial (Caldwell or AP Axial (Reverse Caldwell) radiograph's? | Equal distance from mid lateral orbital margins to lateral wall of cranium on each side to assess for rotation. |
| When using a 30 degree caudad angle for the AP axial (Towne Method) projection of the skull, which positioning line should be perpendicular to the IR? Which cranial bone is best demonstrated with the Towne Method? | The OML (OrbitoMeatal Line). The Occipital bone. |
| What is a fracture that may produce an air-fluid level in the sphenoid sinus? | Basal Skull Fracture |
| What is a destructive lesion with irregular margins? | Osteolytic Neoplasm |
| What is another name for a "PIng Pong" fracture? | Depressed skull fracture |
| What is a tumor that may produce erosion of the Sella Turcica? | Pituitary Adenoma |
| What's another name for Osteitis Deformans? | Paget's Disease |
| What's the name for a tumor that originates in the bone marrow? | Multiple Myeloma |
| Does Paget's disease require an increase in exposure factors? | Yes |
| On a properly positioned AP Axial (Towne's Method) projection, where should the Dorsum Sellae be placed into the middle aspect of? | Foramen Magnum |
| If the patient cannot flex their neck to bring the OML perpendicular to the IR, what positioning line can the technologist bring perpendicular to the IR and how much CR angle? | The IOML can be perpendicular and the CR angle can be 37 degrees caudad instead of 30 degrees caudad. |
| Where is the CR centered for a lateral skull? Where is the CR centered for a lateral projection of the Sellae Turcica? | 2" superior to the EAM, halfway between the Frontal Eminence and the Inion, or $5 degrees anterosuperior (diagonal) from the TEA. For the Sella Turcica the CR should be centered 3/4" anterosuperior to the EAM. |
| Which skull positioning line is placed parallel to the IR for the SMV projection? | The IOML |
| What CR angle must be maintained for the AP Axial (Towne's Method) projection? How much angle should be used when positioning the IOML perpendicular to the IR? Where is the centering for the Towne's? Which part should the CR traverse through? | 30 degrees caudad to the OML? 37 degrees caudad.Center to the mid sagittal plane 2 1/2 " superior to the Glabella, or 1 1/2" superior to the Superciliary Arch. Through the Sellae Turcica (3/4" anterosuperior to EAM) |
| What is the Haas Method (WHich projection and CR angle)? Which level should the CR exit at? | A PA axial skull with the CR angled 25-30 degrees cephalic. CR should exit 1 1/2" superior to the Nasion. |
Created by:
jamestkelley