Chapter 7: Extraoral Radiographic Projections Flashcards
What do we examine in Extraoral Radiographic projections:
- the areas not fully covered by intraoral films such as:
1. Cranium
2. Face: maxilla and mandible
3. Cervical spine
Pathological purposes of an extraoral radiographic projection:
- diseases
- impacted teeth
- trauma
- TMJ
- abnormalities
DATA TI
Treatment purposes of an Extraoral radiographic projection:
- relationships between orofacial and dental structures
- growth and development
- treatment progression
GRT
X-ray units components?
- machine
- films
- intensifying screen
MIF
3 types of X-ray machines:
- conventional dental xray machines
- panoramic machines
- higher capacity medial xray units
Dimensions of the film?
13 x 18 - 20 x 25 cm
The anatomical imaging planes:
Relate to positions in space and are found at right angles to each other
The 3 anatomical planes are?
- Frontal/coronal
- Sagittal/lateral
- Transverse/horizontal/axial
The frontal/coronal plane:
- splits the body into?
- vertical or horizontal
- example
- splits body into front and back halves
- vertical
- dorsal-ventral, back-front, posterior-anterior parts
- panoramic xray
The sagittal/lateral plane:
- splits the body into?
- vertical or horizontal
- parallel to the?
- example
- into left and right halves
- vertical
- sagittal suture
- CBCT
The transverse/axial plane:
- splits the body into?
- vertical or horizontal
- where is the x-ray
- example
- upper and lower halves, cranial and caudal
- horizontal
- on top or below the patient
- occlusal xray
The cephalometric landmarks consist of ___ landmarks and ___ planes/line?
12, 3
The cephalometric landmarks are?
- Glabella
- Nasion
- Orbitale
- Naso-spinal
- Gnathion
- Gonion
- Condylion
- Cigion
- Porion
- Ionion
- Lambda
- Bregma
The cephalometric planes/lines are?
A. Frankfurt plane
B. Canthomeatal line
C. Auricular line
What are the 3 types of extraoral Radiographic projections?
- Frontal skull projection
- Lateral skull projection
- Submentovertex (base) projection
The frontal skull projection is divided into?
Posteroanterior skull projection and anteroposterior skull projection
And then the posteroanterior skull projection is also divided into 2 techniques which are?
- occipital frontal film
- occipital mental film
2 variations of the posteroanterior skull projection are?
Grasey
Blondeau
Occipital frontal film:
- film/receptor:
- head:
- x-ray beam:
- canthomeatal line:
- patient:
- setbacks
- in front of the patient
- canthomeatal line is perpendicular to the film/receptor
film is vertical, canthomeatal line is horizontal - xray beam: from behind the patient, perpendicular to the receptor from posterior to anterior, and parallel to the canthomeatal line
- canthomeatal line is parallel to the xray beam
- uptight positon
- overlapping
What can we study with a posterior anterior skull projection (Occipital frontal film)?
- facial growth
- trauma
- frontal sinuses and TMJ
- orbits
- nasal cavity
- calvaria: bones around the neuro cranium (occipital, temporal,..)
What structures can we analyse with a posterior anterior skull projection (Occipital frontal film)?
- calvaria
- sutures
- external auditory meatus
- mastoid air cells
- temporal bone
- orbits
- sinuses (frontal, ethmoid, maxillary)
- zygomatic process
- nasal cavity
- middle and inferior turbinates
- nasal septum
- hard palate
- mandible: condyle and coronoid process, ramus, angle, and body
Interpretation of a posterior anterior skull projection (Occipital frontal film)?
Steps: (5)
Step 1: calvaria, sutures, intracranial calcifications, mastoid air cells, Petrous ridge, compare both sides, symmetry
Step 2: upper and middle face: orbits, sinuses, zygomatic processes, nasal cavity, middle and inferior turbinates, nasal septum, hard palate
Step 3: lower face (mandible): condyle, coronoid process, ramus, angle, body
Step 4: cervical spine: dens, superior border of C2, inferior border of C1
Step 5: alveolar bone and teeth
Occipital mental film is also known as the ____ projection?
WATERS
Occipital mental film:
- film/receptor:
- head:
- mouth:
- x-ray beam:
- canthomeatal line:
- patient:
- indications:
- to analyse:
Xray from behind but angulated
- in front of the patient
- tilted upwards so that the canthomeatal line forms a 37 degree angle with the receptor/film
- open/closed
- perpendicular to the receptor from posterior to anterior
- canthomeatal line forms a 37 degree angle with receptor/film
- patient in upright position
- maxillary sinuses and trauma
- to analyse the maxillary sinus
Grasey?
- mouth:
- xray beam:
- open
- naso mento film
GO
Blondeau:
- mouth:
- xray beam:
- closed
- naso meto film, 20 degrees vertical
BC
Anteroposterior skull projections are also known as?
TOWNE
Anteroposterior skull projection:
- film/receptor:
- head:
- x-ray beam:
- mouth:
- indications:
- perpendicular to the floor , behind the patient
- tilted downwards so that the canthomeatal line forms a 25-30 degree angle with the receptor
- xray beam: 25-30 degree angle to canthomeatal line, in front of patient
- open and chin to chest
- condyle fractures, mandibular ramus
Lateral skull projections: (lateral cephalometric projections)
- film/receptor:
- head:
- x-ray beam:
- parallel to the patient’s mid sagittal plane
- site of interest towards/ touching receptor
- perpendicular and centered over the external auditory meatus
Structures seen in a lateral skull projection:
- base of the skull
- calvaria
- mastoid air cells
- Clivus
- chinois process
- sella turca
- sphenoid sinuses
- roof of the orbit
- orbits
- sinuses
- ptergomaxillary fissures
- pterygoid plates
- zygomatic process
- anterior nasal spine
- mandible
- cervical spine
- vertebra
Cephalometric analysis:
- used for?
- who uses it?
- 2 types of cephalometric analyses?
- frankfurt plane parallel to?
- occlusal position:
- sagital plane parallel to?
- central xray beam is ?
- analysis of the dental and skeletal relationships in the head. Soft tissues, facial growth
- dentists, orthodontics, oral and maxillofacial surgeons (orthognathic surgery)
- Steiner, rickettes
- floor
- all teeth should mesh together
- film/receptor
- perpendicular and centred over external auditory meatus
A technique of the lateral skull projection is ?
Schuller technique
Schuller technique:
- face:
- used for:
- structures analysed:
- face resting but slightly rotated
- mandibular fractures
- mastoid air cells, external auditory canal, tympanic cavity, mandible, TMJ
Submentovertex (base) projection is also known as?
HIRTZ
Submentovertex (base) projection:
- film/receptor:
- head:
- canthomeatal line:
- x-ray beam:
- could use to asses:
- parallel to the patients transverse plane
- patient’s neck is extended as far backwards as possible
- canthomeatal line is parallel to the film
- xray beam is perpendicular to the transverse plane , canthomeatal line, and the film
- to asses impacted canines
Indications of the submentovertex skull projections:
- paranasal sinuses
- TMJ
- zygomatic arch
- base of the skull
- mandible ramus
- hard palate
Panoramic projections:
- comprehensive Radiographic examination
- oral and maxillofacial surgery
- study of the systematic manifestations in the oral cavity and maxillofacial region
- dental infections
- periodontics, orthodontics, etc
- implantology
- forensic and legal dentistry
