Radiographic Positioning Skull and Vertebra PDF

RADIOGRAPHIC POSITIONING SKULL AND VERTEBRA FGBREYES, RRT, CVT, MSRT  MORPHOLOGY The morphology, or variations in how these attachments evolved tells us much about the particular animal's adaptations to their environment. (exceptions include O...

RADIOGRAPHIC POSITIONING SKULL AND VERTEBRA FGBREYES, RRT, CVT, MSRT  MORPHOLOGY The morphology, or variations in how these attachments evolved tells us much about the particular animal's adaptations to their environment. (exceptions include Old World primates such as humans, in which the middle ear cavity is Canis latrans auditory bulla enclosed within the temporal bone but not within a bulla). SKULL MORPHOLOGY MESOCEPHALIC Average head 15 cm between parietal eminences 19 cm from the frontal eminence to inion 23 cm from vertex to chin. Temporal base or petrous pyramid forms an angle of 45° to 47° to the MSP. SKULL MORPHOLOGY BRACHYCEPHALIC Short from front to back Broad from side to side Shallow from vertex to base Petrous pyramid forms an angle greater than 47° (approximately 54°) to the MSP. The width is 80% or greater than the length SKULL MORPHOLOGY DOLICOCEPHALIC Head is long from front to back Narrow from side to side Deep from vertex to base. Petrous pyramid form an angle less than 47° (approximately 40°) to the MSP The width is less than 75% of the length. CRANIAL TOPOGRAPHY SURFACE LANDMARKS Midsagittal Plane or Median Plane (MSP) Symmetrically divides the body into left and right halves. Interpupillary Line or Interorbital Line (IPL) Connecting the pupils or outer canthi of the eyes Supraorbital Groove (SOG) Slight depression above each eyebrow. Corresponds to the anterior fossa of the cranial vault. Supraorbital Margin (SOM) Superior rim of each orbit. CRANIAL TOPOGRAPHY SURFACE LANDMARKS Pinna or Auricle Large flap of cartilage at the external portion of the ear Tragus Small flap cartilaginous flap covering the ear. Top of the Ear Attachment (TEA) Superior attachment of the auricle Same level of petrous ridge Canthi/Canthus Junction of the upper and lower eyelids CRANIAL TOPOGRAPHY SURFACE LANDMARKS Gonion/Angle of the Mandible The lower posterior angle on each side of the jaw or mandible Mental Point The midpoint of this triangular area of the chin as it appears from the front. Glabellomeatal Line (GML) It is a line between the glabella and EAM Orbitomeatal Line (OML) Frequently used positioning line located between outer canthus and the EAM. Also called the RADIOGRAPHIC BASE LINE. CRANIAL TOPOGRAPHY SURFACE LANDMARKS Infraorbitomeatal Line (IOML) Reids base line - often used as the imaging reference line in brain CT scanning Line of Frankfurt - a line extending from the most inferior point of the orbital margin to the left tragion. Anthropological base line - passes from the infraorbital point to the upper border of the EAM (also known as the Frankforterline) Base line of the cranium It is a line which connects the infra-orbital point to the EAM CRANIAL TOPOGRAPHY SURFACE LANDMARKS Infraorbitomeatal Line (IOML) Reids base line - often used as the imaging reference line in brain CT scanning Line of Frankfurt - a line extending from the most inferior point of the orbital margin to the left tragion. Anthropological base line - passes from the infraorbital point to the upper border of the EAM (also known as the Frankforterline) Base line of the cranium It is a line which connects the infra-orbital point to the EAM CRANIAL TOPOGRAPHY SURFACE LANDMARKS OML AND GML There is an approximate 8° average angle difference between the OML and GML OML AND IOML There is an average difference of 7° exists between the angles of the OML and IOML IOML AND AML There is an average difference of 15° exists between the angles of the IOML and AML CRANIAL TOPOGRAPHY SURFACE LANDMARKS Acanthiomeatal Line (AML) It is a line between the acanthion and EAM Interpupillary Line (IPL) It joins the center of the two orbits or pupils Mentomeatal Line (MML) It is a line between the mental point (mandible) and EAM. CRANIAL TOPOGRAPHY SURFACE LANDMARKS Lips to Meatal Line (LML) It is a line between the junctions of the lips to the EAM. Glabelloalveolar Line Connects the glabella to a point at the anterior aspect of the alveolar process of the maxilla. Auricular Line It is perpendicular to the anthropological base line and passes through the EAM CRANIAL TOPOGRAPHY SURFACE LANDMARKS SKULL AP PROJECTION OML perpendicular to the IR CR perpendicular to nasion. Best demonstrate the frontal and parietal bones. Petrous pyramid fills the orbit SKULL PA AXIAL PROJECTION CADWELL’S METHOD Prone Forehead and nose OML is perpendicular to IR MSP is perpendicular to midline of the table. CR 15° caudad to nasion Best demonstrate alveolar ridge fractures. General survey examination of the cranium. Petrous pyramid in the lower 1/3 of the orbits SKULL PA AXIAL PROJECTION CADWELL’S METHOD MODIFICATION CALDWELL’S METHOD 23° caudad to nasion. Glabellomeatal Line (GML) perpendicular to IR 20° to 25° caudad to mid-orbit Demonstrate superior orbital fissures 25° - 30° Caudad Demonstrate rotundum foramina Petrous pyramid projected below the inferior orbital margin. SKULL PA AXIAL PROJECTION TOWNE’S/GRASHEY METHOD MODIFICATION OML perpendicular to film plane (chin depressed) IOML perpendicular to film plane (Patient unable to flex their neck). CENTRAL RAY: 1. 30° caudad to OML perpendicular to IR 2. 37° caudad to IOML perpendicular to IR 3. 40° - 60° caudad Foramen magnum and jugular foramina 2.5 in.(6 cm) above glabella Best demonstrate the occipital bone Posterior clinoid process within the shadow of the foramen magnum. Excessive angulation of CR projects the posterior C1 arch in the foramen magnum. Under angulation of the CR projects the dorsum sella above foramen the magnum. SKULL PA AXIAL PROJECTION TOWNE’S/GRASHEY METHOD MODIFICATION SKULL PA AXIAL PROJECTION HAAS METHOD Prone position Forehead and nose OML perpendicular to IR CR 25° cephalad to 1.5 in. inferior to the inion and exiting 1.5 in. above nasion. Also called Reverse Towne’s projection For hypersthenic or kyphotic, obese and other patients who cannot be adjusted for AP axial projection. Best demonstrate the occipital bone with magnification SKULL PA AXIAL PROJECTION HAAS METHOD SKULL LATERAL MSP is parallel to IR IPL is perpendicular to IR IOML perpendicular to front edge of the cassette. CR perpendicular to 2 inches above EAM Best demonstrate the parietal bones. Sella tursica and clivus are demonstrated in profile. SKULL LATERAL Crosstable or Shoot- Through Lateral Projection demonstrating traumatic sphenoid effusion which is an indication of a basal skull fracture. SVM (SUBMENTOVERTIAL) - FULL BASAL PROJECTION / SCHULLER METHOD Head resting on vertex MSP is perpendicular to IR IOML is parallel to IR. CR to ¾ inch (2 cm) anterior to level of EAMs Best demonstrate the base of the skull Demonstrate the basilar portion of the occipital bone. Mandibular condyles anterior to petrous pyramids. VERTICOSUBMENTO- FULL BASAL PROJECTION / SCHULLER METHOD Distorted and magnified image of the midbase due to increase OID and angulation of CR. Useful for studies of anterior cranial base and sphenoid sinuses. Best projection for foramen ovale and spinosum. Alternative projection for SMV projection. Mandibular condyles anterior to petrous pyramids. AXIOLATERAL - LYSHOLM METHOD Head in lateral position. CR 30°-35° caudad exit at a point 1 inch (2.5 cm) distal to the lower EAM Alternative projection for SMV projection for patient who cannot extend their neck. Oblique position of the lateral base of the cranium closest to the IR. SELLA TURSICA - LATERAL PROJECTIONS Sella Tursica Turkish Saddle Posterior Clinoid Process Small extensions superior to the dorsum sellae. Dorsum Sellae Back of the saddle Posterior wall of sella tursica. Clivus Shallow depression just posterior to the base of the dorsum sellae. Forms a base of support for the pons portion of the brain. SELLA TURSICA - PA AXIAL PROJECTION - HAAS METHOD 1) 25° cephalad to 1.5 inches Reverse Towne’s projection inferior to the inion and exiting 1.5 inches above 25° cephalad nasion Dorsum sellae and posterior clinoid processes projected within the 2) 10° cephalad shadow of the foramen magnum. This is an alternative 10° cephalad projection for demonstrating Dorsum sellae is projected above the dorsum sella, posterior the foramen magnum. clinoid, foramen magnum and petrous ridge. PARANASAL SINUSES PARANASAL SINUSES Large air-filled cavities Should be radiographed in erect/upright position. To demonstrate the presence of air-fluid level. To differentiate between shadows caused by fluid and those caused by other pathologic conditions. Patient must be in erect at least 5 minutes before taking the examination. FEMS Frontal Sinuses - Frontal (cranial) bone Ethmoid - Ethmoid (cranial) bone Maxillary Sinuses - Maxillary (facial) bone Sphenoid - Sphenoid (cranial) bone PARANASAL SINUSES (PNS) - LATERAL PROJECTIONS CR 15° caudad to nasion Best projection to demonstrate the frontal sinuses and anterior ethmoidal sinuses. Petrous ridge are projected into lower 1/3 of the orbits. PARANASAL SINUSES (PNS) -WATERS METHOD Patient head is resting on CR directed to acanthion. chin. Best demonstrate the maxillary MML is perpendicular to IR sinuses above the petrous ridge. OML forms an angle of 37° Useful projection for demonstrating the foramen with the plane of the film. rotundum. Tip of the nose ¾ inch Petrous pyramids below the from the image receptor. maxillary sinuses. Demonstrate any retention cyst and possible nasal deviation PARANASAL SINUSES (PNS) -WATERS METHOD Any step deformity in the lines would indicate a fracture of that particular facial bone. PARANASAL SINUSES (PNS) -CALDWELL’S METHOD CR 15° caudad to nasion Best projection to demonstrate the frontal sinuses and anterior ethmoidal sinuses. Petrous ridge are projected into lower 1/3 of the orbits. Caldwell view showing radiographic features of frontal sinus: Scalloping of the superior border, septa, and supraorbital cells PARANASAL SINUSES (PNS) -CALDWELL’S METHOD VS. WATERS METHOD PARANASAL SINUSES (PNS) - PARIETOACANTHIAL TRANS-ORAL PROJECTION OPEN MOUTH WATERS Demonstrate the sphenoid Indications sinuses through the open It can be used to assess for mouth. facial fractures, as well as for acute sinusitis. The open mouth projection removes the upper teeth from direct superimposition of the sphenoid. This is an angled PA radiograph of the skull, with the patient gazing slightly upwards. PARANASAL SINUSES (PNS) - PARIETOACANTHIAL TRANS-ORAL PROJECTION PIERRE METHOD Head resting on nose and chin Instruct the patient to phonate “ah” softly during exposure. Direct CR at 30° caudad to MSP (a line extending from the sella tursica to the center of the open mouth) Demonstrate an axial image of the sphenoid sinuses projected through the open mouth. PARANASAL SINUSES (PNS) - SUVMENTOVERTICO PROJECTION CR perpendicular between the angles of the mandible. Best demonstrate a basal projection of the sphenoid, ethmoid and maxillary sinuses. FACIAL BONES - LATERAL PROJECTIONS Zygoma is centered to MLT CR perpendicular to mid- zygoma (midway between outer canthus and EAM) Useful for demonstrating depressed fractures of the frontal sinus. Superimposed mandibular rami, orbital roof FACIAL BONES - WATERS PROJECTION Demonstrate an axial image of the facial bones. Best single projection for demonstrating the entire facial bone. Petrous ridge below the maxillary sinus. Useful for demonstrating fractures of the orbit and fractures of the nasal wings. FACIAL BONES - MODIFIED WATERS PROJECTION Prone position Demonstrates facial Patient head is resting on bones with less axial chin and nose. angulation. LML is perpendicular to Petrous ridges are projected into table lower-half of the maxillary sinuses. OML forms an angle of Best demonstrates a 55° with the film. more direct view of the CR Perpendicular to orbital rim as compared acanthion with Waters projection. FACIAL BONES - AP AXIAL PROJECTION REVERSE WATERS PROJECTION Patient in supine position. IOML is perpendicular to IR 30° Cephalad – CR will enter the face or slightly below the lips and exits 2 nches above the inion. CR must be parallel to MML. Demonstrate an axial position of the superior facial bone (similar to waters projection), although the structures are magnified. NASAL BONE LATERAL PROJECTION - (SOFT TISSUE LATERAL) CR perpendicular to 1⁄2 inch inferior to nasion Best position to demonstrate non- displaced linear fractures of the nasal bone. Soft tissue structure of the nose. Nasal bones Nasofrontal suture Anterior nasal spine NASAL BONE SUPEROINFERIOR TANGENTIAL (AXIAL) PROJECTION Patient in prone position or upright seated on chair. CR center to nasion and parallel to GAL Primarily used to demonstrate medial or lateral displacements of fragments in fractures. Demonstrates mid to distal nasal bones in a tangential perspective. ZYGOMA - SUBMENTOVERTICO PROJECTION CR perpendicular to IOML to a point midway between zygoma 1 1⁄2 - 2 inches inferior to mandibular symphysis Also known as the TEA CUP OR JUGHANDLER’S VIEW Demonstrate the lateral margins of the zygomatic arches free of superimposition ZYGOMA TANGENTIAL POSITION: OBLIQUE INFEROSUPERIOR PROJECTION Patient in SMV position Slightly oblique Rotate head/MSP 15° tangential image of toward side being one zygomatic arch examined, then tilt chin free of 15° toward side of interest superimposition. CR Perpendicular to Useful with patients IOML and center to who have depressed zygomatic area of interest fractures or flat approximately 1 1⁄2 inches cheekbones. posterior to outer canthus ZYGOMA TANGENTIAL POSITION: OBLIQUE INFEROSUPERIOR PROJECTION ZYGOMA - MODIFIED FUCHS METHOD CR - 35° caudad and Patient in prone position enters the most prominent Rest cheek of the point of the zygoma affected side on table farthest from film. Oblique position of the AML perpendicular to IR uppermost zygomatic arch Rotate head so that free of superimposition. MSP forms 45° then tilt Lateral portion of maxillary head 15° (rotation and sinus is also well demonstrated. tilt ensure that CR will be Unilateral zygomatic tangent to the lateral arch free from overlying surface of the skull. structures. ZYGOMA - MODIFIED TOWNE’S METHOD 30° caudad to OML perpendicular to IR 37° caudad to IOML perpendicular to IR 1 inch (2.5cm) above glabella Shows the symmetric view of both zygoma ZYGOMA - ZYGOMA MAY METHOD Single zygomatic arch Patient in prone position, free of superimposition. neck extended. CR perpendicular to Rest chin on table IOML to 1 1⁄2 inches Rotate head away from posterior to outer the side being examined so that MSP canthus. forms 15° then tilt head Best projection for 15°. patients who have IOML as nearly parallel to depressed fractures or IR flat cheekbones.