Skull, Facial Bones, and Sinuses
How many bones make up the skull?
22 bones (8 cranial, 14 facial)
Dolichocephalic petrous ridges lay at ________ degrees from the MSP.
40
Mesocephalic petrous ridges lay at _______ degrees from the MSP.
47
Bradycephalic petrous ridges lay at ______ degrees from the MSP.
54
What are the 4 groups of sinuses?
Frontal Ethmoidal Sphenoidal Maxillary
What is the PA Axial Caldwell used to view?
demonstrate the orbits with the petrous ridges in the lower 1/3
Parietocathial Waters Method- Sinuses
demonstrates the maxillary sinuses and will do a SMV projection to demonstrate the ethmoidal and sphenoid sinuses
Brachycephalic
head is wider than long, petrous ridges lay 54 degrees from MSP
Tri-pod fracture
impact the side of face below the eye, orbit is bigger and more open
Dolichocephalic
long narrow head, petrous ridges lay at 40 degrees from MSP
Reference point: Glabella
midway between the eyebrows
Midsagittal plane
separate the skull into equal right and left halves
Coronal
separates skull into anterior and posterior portions
Transverse (horizontal) plane
separates skull into superior and inferior portions
Sagittal plane
separates skull into unequal right and left portions
Mid-coronal plane
separates the anterior and posterior into two equal halves
Structures shown on LAT skull
cranium halves are stacked on one another, sella turcia, anterior clinoid process, dorsum sellae, and posterior clinoid process. ** you most likely will not see the mandible
Reference point: Acanthion
cupids bow
LAT Skull- Left/Right
**affected side closest to the IR. IR- 10x12 SID- 40" CR- perpendicular to the IR entering 2 in. above the EAM Respiration- suspend.
PA Axial Caldwell Method- Skull
IR- 10x12 SID-40" CR- angled 15 degrees caudad exiting the nasion Position of part- OML perpendicular to IR Respiration- suspend
Submentovertical (SMV) - Schuller Method- Skull
IR-10x12 SID- 40" CR- directed through the sella turcia perpendicular to the IOML, enters MSP of the throat between the mandible and a point of 3/4 in anterior to the EAM Position of part- place the IOML as parallel as possible Respiration-suspend
PA Axial Caldwell Method- Facial Bones
IR-10x12 SID- 40" CR- directed 15 degrees caudad, exiting the nasion Patient position- prone or seated upright with head and nose resting on board. Adjust the head til the OML is perpendicular to the IR. Respiration- suspend
If patient can't flex the neck enough to place the OML perpendicular to IR, you can place the ________ perpendicular to the IR and add __________ to the CR.
IOML, 7 degree
Lateral- Affected Side- Sinuses
IR- 10x12 SID- 40 or 72 for pre-op CR- perpendicular to the IR entering 1 inch posterior to the outer canthus. Patient position- upright with patient in an RPO or LPO position, rest patient head in true lateral with MSP parallel to the IR and IOML perpendicular to the front edge of the IR.
AP Axial Towne Method- Skull
IR- 10x12 SID- 40" CR- angled 30 degrees caudad entering 2.5 inches above the glabella and exiting the foramen magnum Position of part- place the patients MSP and flex the neck so the OML is perpendicular to the IR Respiration- suspend
LAT-Facial bones
IR- 10x12 SID- 40" CR- perpendicular and entering the zygomatic bone halfway between the outer canthus and the EAM Patient position- upright or recumbent, adjust patients head until MSP is parallel with the IR and the IOML is perpendicular to the edge of the IR. Respiration- Suspend
Open- mouth Waters Method- Sinuses
IR- 10x12 SID- 40" CR- perpendicular to the IR and exiting the acanthion Patient position- rest patients chin on IR, make sure OML forms a 37 degree angle with IR. have patient slowly open mouth.
Trauma LAT skull
IR- 10x12 SID- 40" CR- perpendicular to the IR entering 2 in. above EAM Patient postion- supine with head supported if no known cervical fracture. Respiration- suspend
Parietocanthial (Waters) Method- Facial Bones
IR- 10x12 SID- 40" CR- perpendicular to the IR exiting the acanthion Position of part- hyperextend the neck so the OML forms a 37 degree angle to the IR. Respiration- suspend
PA Axial Caldwell- Sinuses
IR- 10x12 SID- 40" CR- perpendicular to the IR exiting the nasion Patient position- seated or upright facing the IR. Respiration- hold breath
PA Caldwell Method- Skull
IR- 10x12 SID- 40" CR- perpendicular to the IR exiting the nasion. Position of part- place the OML perpendicular to IR Respiration- suspend
What projection for the sinuses shows all of the paranasal sinuses?
Lateral of affected side
Routine Views for sinuses
PA Axial (Caldwell) Semi-Axial Transoral Lateral-affected side
Radiographic lines: Acanthomeatal line
acanthion to the EAM
Blow-out fracture
accidents or big impacts to the sinuses, orbital rim is fractured
Mesocephalic
average persons skull, petrous ridges lay 47 degrees from MSP
What are the types of skull fractures?
blow-out and tri-pod
Acabthioparietal Reverse Waters Method- Facial Bones
can be done if patient cannot tolerate the Waters position.
PA Axial Projection Caldwell Vertical Grid- Sinuses
extend the patient's neck slightly rest the tip of nose on the bucky and center the nasion to the IR. position the patients head so that the OML forms an angle of 15 degrees with the CR. you may use a sponge to support the head between the forehead and bucky.
Radiographic lines: Orbitomeatal line (OML)
from corner of eye to the EAM
Radiographic lines: Infraorbitomeatal line (IOML)
from the bottom of the eye to the EAM
What are the cranial bones?
frontal, parietal, temporal, occipital, sphenoid, ethmoid
Radiographic lines: Glabellomeatal line
glabella to the EAM
What is the angle of the mandible called?
gonion
Reference point: Inner & outer canthi
inner and outer corners of the eye
Radiographic lines: Mentomeatal line (MML)
mental point to the EAM
Reference point: Nasion
mid way between the eyes
Glabelloalveolar line (GAL)
runs down front of face
PA Axial Haas Method- Skull
this method will produce a comparable image to the AP Townes.
Radiographic lines: Interpupillary line
through the pupils
PA Axial Caldwell Angled Grid- Sinuses
tilt the vertical grid down 15 degrees, rest the patients nose and forehead on the bucky and center the nasion to the IR. this positions the OML perpendicular to the angled IR and 15 degrees horizontal to the CR
Reference point: Mental point or symphysis
tip of the chin
What is the PA Caldwell Method used for?
used when the frontal bone is of primary interest