RADPOS - Cranium

• Lateral projection

• PA / PA axial projection (Caldwell Method)

• AP / AP axial projection

• AP axial projection (Towne Method)

• PA axial projection (Haas Method)

(5) Cranium projections

• SMV projection (Schuller Method)

• VSM projection (Schuller Method)

(2) Cranial base

• Lateral projection

• AP axial projection

• PA axial projection

(3) Sella turcica

22

Number of bones that make up the skull

8

Number of cranial bones in the skull

14

Number of facial bones in the skull

Calvaria

Skull dome forming the roof of the cranium

Sutures

Fibrous joints joining skull bones (except mandible)

Coronal suture

Suture between frontal and parietal bones

Sagittal suture

Suture between two parietal bones along the midline

Lambdoidal suture

Suture between occipital and parietal bones

Pterion

Skull region where several bones meet; overlies middle meningeal artery

Fontanels

Soft spots on infant skull where sutures are not yet fused

Mandible

Largest, strongest facial bone; forms lower jaw

Temporomandibular joint

Articulation of mandible and temporal bone; only movable skull joint

Sphenoid

Keystone bone articulating with all other cranial bones

Foramen magnum

Large opening for spinal cord located in the occipital bone

External auditory meatus

Ear canal in temporal bone

Auditory ossicles

Malleus, incus, and stapes bones transmitting sound in middle ear

Hyoid

Bone in neck that anchors tongue; does not articulate with other bones

Orbit

Eye socket composed of 7 bones (frontal, sphenoid, ethmoid, maxilla, zygoma, lacrimal, palatine)

Ethmoid

Bone forming part of nasal septum and medial orbital walls

Nasal conchae

Scroll-shaped bones in nasal cavity for air filtration and humidification

Tympanic membrane

Eardrum transmitting sound vibrations

Sella turcica

Pituitary gland seat in sphenoid bone

Asterion

Suture junction of parietal, occipital, and mastoid portion of temporal bone

Basal Fracture

Fracture located at the base of the skull

Blowout Fracture

Fracture of the floor of the orbit

Contre-coup Fracture

Fracture to one side of a structure caused by trauma to the other side

Depressed Fracture

Fracture causing a portion of the skull to be depressed into the cranial cavity

Leforte Fracture

Bilateral horizontal fractures of the maxillae

Linear Fracture

Irregular or jagged fracture of the skull

Tripod Fracture

Fracture of the zygomatic arch and orbital floor or rim and dislocation of the frontozygomatic suture

Mastoiditis

Inflammation of the mastoid antrum and air cells

Metastases

Transfer of a cancerous lesion from one area to another

Osteomyelitis

Inflammation of bone due to a pyogenic infection

Osteopetrosis

Increased density of atypically soft bone

Osteoporosis

Loss of bone density

Paget's Disease

Thick, soft bone marked by bowing and fractures

Polyp

Growth or mass protruding from a mucous membrane

Sinusitis

Inflammation of one or more of the paranasal sinuses

TMJ Syndrome

Dysfunction of the temporomandibular joint

Acoustic Neuroma

Benign tumor arising from Schwann cells of the eighth cranial nerve

Multiple Myeloma

Malignant neoplasm of plasma cells involving the bone marrow and causing destruction of the bone

Osteoma

Tumor composed of bony tissue

Pituitary Adenoma

Tumor arising from the pituitary gland, usually in the anterior lobe

Interpupillary line

Horizontal line connecting the centers of the pupils in both eyes

Acanthion

Midpoint at the base of the anterior nasal spine, located at the junction of the upper lip and nose

Outer canthus

Outer corner of the eye where the upper and lower eyelids meet

Infraorbital margin

Lower bony edge of the orbit (eye socket)

External acoustic meatus

Opening of the ear canal on the side of the head

Orbitomeatal line

Line from the outer canthus of the eye to the center of the external acoustic meatus

Infraorbitomeatal line

Line from the infraorbital margin to the external acoustic meatus

Acanthiomeatal line

Line from the acanthion to the external acoustic meatus

Mentomeatal line

Line from the mental point (chin) to the external acoustic meatus

Mesocephalic

Skull shape with petrous pyramids projecting anteriorly and medially at a 47-degree angle from the midsagittal plane; represents an average or typical skull form.

Petrous pyramids

Dense, pyramid-shaped portions of the temporal bones containing the inner ear structures; their superior borders are at the base of the cranium.

Brachycephalic

Short front-to-back, broad side-to-side, and shallow vertex-to-base skull; petrous pyramids form a wider angle (~54 degrees) with the midsagittal plane; internal structures sit higher relative to the infraorbitomeatal line (IOML).

Dolichocephalic

Long front-to-back, narrow side-to-side, and deep vertex-to-base skull; petrous pyramids form a narrower angle (~40 degrees) with the midsagittal plane; internal structures sit lower relative to the IOML.

Perpendicular; external acoustic meatus (EAM)

In the lateral projection of the cranium, the central ray is directed ____________________ to enter 2 inches (5 cm) superior to the _________________.

Midsagittal; interpupillary

During the lateral skull projection, the ________________ plane of the head is placed parallel to the plane of the image receptor (IR), and the ________________ line is perpendicular to the IR.

Caudad; nasion; 15 degrees caudad

For the PA projection (Caldwell Method), the patient's forehead and nose rest on the table or upright Bucky, and the central ray is directed ___________________ exiting the _______________ at an angle of _______________.

Lower third

The PA axial Caldwell method projects the petrous ridges into the _______________ third of the orbits.

Perpendicular; 15 degrees cephalad

The AP skull projection is used when the patient cannot tolerate PA positioning; the central ray is ___________________ or directed to the nasion at an angle of ______________ degrees _______________.

Orbitomeatal line (OML); infraorbitomeatal line (IOML); 7 degrees

In the AP axial (Towne) projection, the patient's neck is flexed so that the ___________________ is perpendicular to the IR. If the neck cannot be flexed enough, the ________________ is made perpendicular and the central ray angulation is increased by ______________ degrees.

Foramen magnum; 30 degrees; 37 degrees

The central ray for the Towne method is directed through the ______________ at a caudal angle of ______________ degrees to the OML or ______________ degrees to the IOML.

Prone or seated upright; 25-degree cephalad; external occipital protuberance (inion); nasion

The PA axial (Haas) method is performed with the patient in the __________ or ___________ position with the OML perpendicular to the IR and the central ray directed at a __________ degree ______________ angle to enter 1 ½ inches (3.8 cm) below the ___________________ and exit 1 ½ inches (3.8 cm) superior to the ______________.

Infraorbitomeatal line (IOML); perpendicular

The submentovertical (SMV) projection requires that the _______________ line be placed as parallel as possible to the plane of the IR, and the central ray is directed ___________________ to the IOML.

Occipital

The SMV projection shows symmetric images of the petrosae, mastoid processes, foramen ovale and spinosum, carotid canals, sphenoidal and ethmoidal sinuses, and the ____________ bone.

Contraindicated; perpendicular

The verticosubmental (VSM) projection is used when the SMV projection is ________________ by the patient's condition. The central ray is directed through the sella turcica ___________________ to the IOML.

External acoustic meatus (EAM)

For the lateral projection of the sella turcica, the IR is centered 1/2 inch (1.9 cm) anterior and 1/2 inch (1.9 cm) superior to the _____________.

Dorsum sellae; posterior clinoid processes

In the AP axial projection of the sellar region, a 37-degree caudal angulation projects the ______________ and ______________ within the foramen magnum.

Glabella; cephalad

The PA axial projection central ray is directed to exit the ______________ at a 10-degree _________________ angle.

• Lateral Projection (Cranium)

• PA / PA Axial Projection (Caldwell Method)

• AP Axial Projection (Towne Method)

• PA Axial Projection (Haas Method)

• SMV Projection (Schüller Method)

• Lateral Projection of Sella Turcica

• AP Axial Projection of Sella Turcica

• PA Axial Projection of Sella Turcica

Projections that is Seated-Upright

• AP / AP Axial Projection

• AP Axial Projection (Towne Method)

• SMV Projection (Schüller Method)

• VSM Projection (Schüller Method)

• Lateral Projection (Cranium)

Projections that is in Supine Position

• PA / PA Axial Projection (Caldwell Method)

• PA Axial Projection (Haas Method)

• VSM Projection (Schüller Method)

• PA Axial Projection of Sella Turcica

Projections that is in Prone Position

• Lateral Projection (Cranium)

• Lateral Projection of Sella Turcica

Midsagittal Plane Parallel to IR Projections

• PA / PA axial (Caldwell)

• AP / AP axial

• Towne

• Haas

• PA axial sella turcica

• AP axial sella turcica,

• SMV

• VSM

Midsagittal Plane Perpendicular to IR Projections

• Lateral Projection (Cranium)

• Lateral Projection of Sella Turcica

Interpupillary line perpendicular to IR Projections

• PA/PA axial (Caldwell)

• AP/AP axial

• Towne

• Haas

• PA axial sella turcica

OML perpendicular to IR Projections

• Lateral Cranium (front edge)

• Towne (if OML can’t be)

• AP axial sella turcica

IOML perpendicular to IR Projections

seated-upright; semiprone

In the lateral projection of the cranium, the patient is positioned _____________ or ________________, resting on the forearm and flexed knee of the elevated side if semi prone.

parallel; perpendicular

For the lateral skull projection, the midsagittal plane of the head is placed ____________ to the image receptor (IR), and the interpupillary line is ____________ to the IR.

perpendicular; parallel

The flexion of the patient’s neck in the lateral projection should position the infraorbitomeatal line (IOML) ____________ to the front edge of the IR and ____________ to the long axis of the IR.

perpendicular; superior

The central ray for the lateral projection of the skull is directed ________________ to enter 2 inches (5 cm) ____________ to the external acoustic meatus (EAM).

prone; seated

In the PA projection / PA axial projection (Caldwell method), the patient is positioned ___________ or ___________ with the midsagittal plane centered to the grid.

nasion; 15 degrees

For the Caldwell method, the central ray is directed to exit the ______________ at an angle of ______________ caudad.

20 to 25; caudad

To demonstrate the superior orbital fissures, the central ray is angled ______________ degrees ______________ through the midorbits.

25; 30; caudad

The central ray angle to demonstrate the rotundum foramina is ______________ to ______________ degrees ______________ directed to the nasion.

perpendicular

When the patient cannot tolerate PA positioning, the AP skull projection is performed with the patient supine and the midsagittal plane and orbitomeatal line (OML) positioned _______________ to the IR.

15 degrees; cephalad

The central ray for the AP axial projection is directed perpendicular or at an angle of ______________ degrees ______________ to the nasion.

perpendicular; perpendicular

For the AP axial (Towne) projection, the patient’s midsagittal plane is ______________ to the midline of the IR, and the neck is flexed enough to make the OML _______________ to the IR.

perpendicular; 7 degrees

If the neck cannot be appropriately flexed in the Towne method, the IOML is made ______________ to the IR, and the central ray angulation is increased by ______________ degrees.

foramen magnum; 30; 37

The central ray for the Towne method is directed through the _______________ at a caudal angle of ______________ degrees to the OML or ______________ degrees to the IOML.

2 ½ inches (6.3 cm); EAM

The AP axial projection center enters approximately ______________ inches (cm) above the glabella and passes through the level of the ______________.

prone; seated-upright; perpendicular

In the PA axial projection (Haas method), the patient is positioned ______________ or ________________, with the midsagittal plane centered and the OML positioned _______________ to the IR.

25 degree; cephalad; below; above

The central ray in the Haas method is directed at a ______________ degree ______________ angle to enter a point 1 ½ inches (3.8 cm) _______________ to the external occipital protuberance (inion) and exit approximately 1 ½ inches (3.8 cm) ______________ the nasion.

parallel; perpendicular

For the SMV projection (Schüller method), the patient’s IOML should be placed as ______________ as possible to the IR, and the central ray is directed ______________ to the IOML.

angles of the mandible; anterior

The central ray entry point for the SMV projection is the midsagittal plane of the throat between the ______________ and passes ½ inch (1.9 cm) ______________ to the level of the EAMs.

prone; perpendicular

The VSM projection is performed with the patient _____________, resting the fully extended chin on the table, and the midsagittal plane positioned ______________ to the IR.