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