Corresponds to the highest level of the facial bones
Interpupillary Line
A line used in positioning to ensure that the skull is in a true lateral position
Gonion
Posterior angle of the jaw
Tragus
The small cartilaginous flap covering the EAM
Outer Canthus
Lateral junction of the eye
Orbitomeatal Line
Line between the mid-lateral orbital margin and the EAM
Glabelloaveolar Line
Line between the glabella and aveolar process of the mandible
Infraorbitomeatal Line
Line between the inferior orbital rim and the EAM
Mentomeatal Line
Line between the mental point and EAM
Glabella
Smooth, slightly raised area between the eyebrows
Inion
The most prominent point of the external occipital protuberance
Nasion
A depression at the bridge of the nose
Parietal Eminence
Distance between these two points would indicate the widest dimension of the skull
Mastoid Tip
This point can also be used in positioning fr he open-mouth C-spine
Erosion is best demonstrated on which projection?
Lateral Projection
Anatomical Landmarks used to evaluate the Lateral Projection
Orbital Lines or Roof Rami Mandible Body of Mandible Anterior/Posterior Clinoids Petrous Pyramids Greater/Lesser Wing of Sphenoid EAM Mastoid Tip
Base of Skull, Mastoid Tip, Occlusal Plane
Perpendicular to the film for the AP Open Mouth C-Spine Projection
CR for routine Caldwell Projection
15 degrees Caudal
Why the sinus x-ray is erect
Air and Fluid Levels
Brachycephalic
Skull angle of 54 degrees between the midsagital plane and long axis of the petrous bone
Mesocephalic
Skull angle of 47 degrees between the midsagital plane and long axis of the pertrous bone
Mesocephalic
Average size Skull
Reids Baseline is also called
IOML or Anthropalogic Baseline
Lateral Skull Potioning, Which baseline is perpendicular to the imaginary line along the front edge ofthe IR
IOML is Perpendicular to Imaginary Line
What Projection and CR angle to demonstrate the Superior Orbital Fissure?
Caldwell, 30 degrees Caudal
Which Baseline is parallel to IR for the Submentovertex Projection (SMV)
IOML is Parallel to IR, Perpendicular to CR
CR and Angle for the Haas Method
25 degrees Cephalad
Petrous Pyramid
Densest bone of the 3 aspects of the temporal bone
Properly positioned AP Axial (Towne) projection should place the dorsum sellae in the middle of?
Foramen Magnum
Lack of symmetry of the Petrous Ridges indcates what problem with a Radiograph of an AP Axia Projection?
Rotation
What Positioning errr is present if te Mandibular Rami are not superimposed on a Lateral Skull Radiograph?
Rotation
With a traum patient, what must b determined before performing the SMV Projection?
C-Spine Injury
Where should the Petrous Ridges be located on well positioned 15 Degree Caldwell?
Lower 1/3 of the Orbit
Where should the Petrous Ridges be located on well positioned 30 Degree Caldwell?
Lower than the lower 1/3 of the Orbit
What Skull projection results in th highest Thyroid Dose
SMV (264 mR)
CR and Patient Position for the Towne Projection ofthe Skull
2 1/2" superior to the Glabella, 30 degrees Caudal to the OML
CR and Patient Position for the Lateral Skull Projection
2" Superior to the EAM, Perpendicular to the IR
CR and Patient Position for the Caldwell Projection of the Skull
PA, OML& MSP Perpendicular to the IR, 15 degrees Caudal exiting the Naison
Routine Skull Series
Towne Lateral Caldwell
Structures best demonstrated on the Towne Projection
Dorsum Sellae within the Foramen Magnum
Structures best demonstrated on the Lateral Projection
Sellae Turcica in Profile, Cranial halves, Orbital Plates, Clinoids ad Rami Superimposed
Structures best demonstrated on the Caldwell Projection
Petrous Pyramids in the lower 1/3 of the Orbit
Special Skull Projections
PA or AP Skull SMV Caldwell Haas (Reverse Towne)
Haas (Reverse Town) Special Projection Patient Position and CR
PA, OML Perpendicular to the IR, 25 Degree Cephalad, Occipital Bone is Magnified
Caldwell Special Projection Patient Position and CR
PA, OML & MSP perpendicular to IR, 30 degrees Caudal, Superior Orbital Fissure, Foramen Rotundum, Inferior Orbital Rim
SMV Special Projection Patient position and CR
Vertex of head on IR, IOML Parallel to IR, CR 3/4" Anterior to EAM & Perpendicular to IOML Petrous Pyramids posterior to mandibular condyles, Sphenoid & Ethmoid Sinuses, Foramen Ovali & Foramen Spinosum
Difference in Degrees between the infraorbitomeatal & orbitomeatal lines
7-8 degrees
Small Irregular Bones occassionally found in the Sutures
Wormain
Bone that contains the Cribiform Plate
Ethmoid
Bone that contains the Foramen Ovale
Sphenoid
Bone assciated with and protects the Hypophysis Gland
Sphenoid
Cranial Bone that Articulates with all other Cranial Bones
Sphenoid
Widest portion of the cranium is formed at a level of?
Parital Tubercles
Lateral Juntion of eyelid
Outer Canthus
Posterior Angle of Jaw
Gonion
Corresponds to the highest (Nuchal) Line ofthe Occipital Bone
Inion
Located at junction of the 2 Nasal Bones & the Frontal Bone
Nasion
Line between the Midlateral Orbital Margin & the EAM
OML
Center Point of the EAM
Auricular Point
Positioning line that is primarily used for the modified Waters Projection
Lips-Meatal Line
Line used in positioning to ensure that the skull is in a true lateral position
Interpupillary line
Average KV for the Skull
Film 65-80 Kv Digital 70-80 Kv
AP Axial (Towne) Skull results in about 10x's more dose to __________ than in a PA Axial (Haas) Projection.
Thyroid
# of Cranium Bones
8
# of Facial Bones
14
4 Cranial Bones that form the Calvaria (Skull) Cap
Frontal Right & Left Parietal Occipital
4 Cranial Bones that form the Floor of the Cranium
Right & Left Temporal Sphenoid Ethmoid
Small Horizontal Plate of the Ethmoid
Cribiform Plate
Vertical Plate of the Ethmoid Bone forming the Upper Portion of the Bony Nasal Septum
Perpendicular Plate
Structure found in the middle of the Sphenoid Bone that surrounds the Pituitary Gland
Sella Turcica
Posterior Aspect of the Sella Turcica
Dorsum Sellae
Which structure of the Sphenoid allows for the passage of the Optic Nerve & is the actual opening into th orbit
Optic Foramen
Which Structure of te Sphenoid Bone help form part of the Lateral Walls of the Nasal Cavities
Medial & Lateral Pterygoid Processes
Radiograph best demonstrates the Sella Turcica
Lateral
Aspect of Frontal Bone forms the Superior aspect of the Orbit
Orbital or Horizontal Portion
Cranial Surtures are________joints
Fiborous or Synarthrodial
Small irregular bones that sometimes develop in adult skull sutures are_________&__________bones & are most frequently found in the________suture.
Sutural & Wormian Bones, Lambdoidal Suture
Superior Rim of Orbit
SOM (Supraorbital Margin)
Notch that separates the Orbital Plates from eachother
Ethmoid Notch
Cranial Bones form the Upper Lateral Walls of the Calvarium
R & L Parietals
Cranial Bone Contains the Foramen Magnum
Occipital
Small Prominence located on Squamous Portion of the Occipital Bone
External Occipital Protuberance or Inion
3 Aspects of Temporal Bones
Squamous Portion Mastoid Portion Petrous Portion
Opening of Temporal Bone serves as a Passageway for nerves of Hearing & Equilibrium
Internal Acoustic Meatus
Width between 75% & 80% of Length
Mesocephalic
Width 80% or more Length
Brachycephalic
Width less than 75% of length
Dolichocephalic
CR Angles & Degree of Rotation stated for basic skull positions are based on the ___________Skull & has a angle of _________degrees between the Midsagital Plane & long axis of the Petrous Bone.
Mesocephalic, 47 degrees
Long, Narrow Skull has an angle of appx ______degrees between the midsagital plane & the long axis of the Petrous Bone
+/- 40 Degrees
Thyroid Dose for SMV projection of skull
200-300 mRad
5 Most Common Errors made during a Skull Radiograph