•Why do you need to understand normal anatomy on an xray?
to enable you to mount and interpret films correctly
so you don't mistake normal anatomic structures for pathologic conditions
Name 2 different types of bone
cortical
cancellous
derived from the latin work cortex, and means outer layer. The dense outer layer of the x-ray beam, and appears radiopaque on a radiograph.
cortical
What type of bone is the inferior border of the mandible made up of?
cortical bone
derived from Latin, and means arranged like a lattice. Soft and spongy bone located between 2 layers of dense cortical bone. Composed of numerous bony trabecuae that form a lattice like network of intercommunicating spaces filled with bone marrow.
cancellous bone
How do bony trabeculea sections appear on a radiograph?
radiopaque
How do bone marrow spaces in cancellous bone appear on a radiograph?
radiolucent
Cancellous bone appears predominantly________________
radiolucent
composed of dense cortical bone and appear radiopaque on dental radiographs. there are 5 terms to describe them
prominences of bone
What are the 5 terms used to describe prominences of bone?
process
ridge
spine
tubercle
tuberosity
marked prominence or projection of bone; an example is the coronoid process of the mandible
process
a linear prominence or projection of bone; example is the internal oblique ridge of the mandible
ridge
A sharp, thorn like projection of bone; example is anterior nasal spine of maxilla
spine
a small bump or nodule of bone; an example is the genial tubercles of the mandible
tubercle
a rounded prominence of bone; example is maxillary tuberosity
tuberosity
true or false. spaces and depressions in bone do not resist the passage of x-ray beam and appear radiolucent on radiographs
true
What are the 4 terms used to describe spaces and depressions in bone?
canal
foramen
fossa
sinus
tube-like passageway through bone that contains nerves and blood vessels; example is mandibular____________
canal
an opening or hole in bone that permits the passage of nerves and blood vessels; example is mental______________of the mandible
foramen
a broad, shallow, scooped-out or depressed area of bone; example is the submandibular_______________of the mandible
fossa
a hollow space, cavity, or recess in bone; example is the maxillary____________
sinus
a bony wall or partition that divides 2 spaces or cavities. it may be present within the space of a fossa, or sinus. it appears radiopaque, in contrast to a space or cavity, which appears radiolucent. An example is the nasal___________
septum
an immovable joint that represents a line of union between adjoining bones of the skull. On dental radiographs, it appears as a thin radiolucent line. An example is the median palatine_____________
suture
Composed of 2 paired bones, but are often referred to as a single bone.
maxilla
described as the architectural cornerstone of the face
maxilla
All of the bones of the face articulate with the maxilla except what?
the mandible
This forms the floor of the orbit of the eyes, the sides and floor of the nasal cavities, and the hard palate. It also supports the upper teeth
maxilla
an opening or hole in the bone that is located at the midline of the anterior portion of the hard palate directly posterior to the maxillary central incisors
incisive foramen or nasopalatine foramen
What nerve exits the maxilla through the incisive foramen?
nasopalatine nerve
how does the incisive foramen appear on a radiograph?
small round or ovoid radiolucent area
2 tiny openings or holes in bone that are located on the floor of the nasal cavity. They are the openings of 2 small canals that extend downward and medially from the floor of the nasal cavity. The canals join together to form the incisive canal and share a common exit, the incisive foramen.
superior foramina of the incisive canal
What nerve exits the maxilla through the superior foramina, travels through the incisive canal, and exits at the incisive foramen?
nasopalatine nerve
What is the radiographic appearance of the superior foramina of the incisive canal?
2 small round radiolucencies located superior to the apices of the maxillary central incisors
the immovable joint between the two palatine processes of the maxilla. It extends from the alveolar bone between the maxillary central incisors to the posterior hard palate
median palatine suture
How does the median palatine suture appear on a radiograph?
a thin radiolucent line bound on both sides by dense cortical bone
true or false. As the median palatine suture fuses with age, it may become less distinct radiographically
true
a smooth depressed area of the maxilla located just inferior and medial to the infraorbital foramen between the canine and lateral incisors
lateral fossa
How does the lateral fossa appear on a radiograph?
on maxillary PA as a radiolucent area between the maxillary canine and lateral incisors
a pear shaped compartment of bone located superior to the maxilla. The inferior portion is formed by the palatal processes of the maxilla and the horizontal of the palatine bones. The lateral walls of this are formed by the ethmoid bone, and the maxillae. And it is divided by a bony portion called the nasal septum
nasal cavity
How does the nasal cavity appear on a radiograph?
a large radiolucent area above the maxillary incisors
A vertical bony wall or partition that divides the nasal cavity into the right and left nasal fossae. It is formed by the vomer bone and a portion of the ethmoid bone and cartilage
nasal septum
How does the nasal septum appear on a radiograph?
on Maxillary PA, appears as a vertical radiopaque portion that divides the nasal cavity; may be superimposed over median palatine suture
a bony wall formed by the palatal processes of the maxilla and the horizontal portions of the palatine bones. It is composed of dense cortical bone, and defines the inferior border of the nasal cavity
floor of nasal cavity
How does the floor of the nasal cavity appear on a radiograph?
on Maxillary PA; a dense radiopaque band of bone above the maxillary incisors
a sharp projection of the maxilla located at the anterior and inferior portion of the nasal cavity
anterior nasal spine
how does the anterior nasal spine appear on a radiograph?
as a V-shaped radiopaque area located at the intersection of the floor of the nasal cavity and the nasal septum
wafer-thin, curved plates of bone that extend from the lateral walls of the nasal cavity. They are seen in the lower lateral portions of the nasal cavity.
inferior nasal conchae
How do the inferior nasal conchae appear on a radiograph?
on maxillary PA; diffuse radiopaque mass within the nasal cavity
paired cavities or compartments of bone located within the maxilla. They are located above the maxillary premolar and molar teeth. They rarely extend anteriorly beyond the canine
maxillary sinuses
How large are the maxillary sinuses at birth? How big do they grow to become?
small pea
expand to occupy a large portion of the maxilla
What do the maxillary sinuses appear like on a radiograph?
maxillary PA; radiolucent area located above the apices of the maxillary premolars and molars
the floor of the maxillary sinus is composed of__________ ____________bone, and appears as a ___________line.
dense cortical
radiopaque
this may be seen within the maxillary sinus. They are bony walls or partitions that appear to divide the maxillary sinus in compartments
septa within the maxillary sinus
How do septa within the maxillary sinus appear?
on maxillary PA; appear as radiopaque lines within the maxillary sinus
may be seen within the maxillary sinus. They are tiny, tube-like passageways through bone that contain blood vessels and nerves that supply the maxillary teeth and interdental areas
nutrient canals withing the maxillary sinus
How do nutrient canals within the maxillary sinus appear on a radiograph?
on maxillary PA; narrow radiolucent band bound by 2 radiopaque lines which represent the cortical bone that comprises the walls of the canal
the intersection of the maxillary sinus and the nasal cavity as viewed on a dental radiograph
inverted Y
How does the inverted Y appear on a radiograph?
appears as a radiopaque upside-down Y formed by the intersection of the lteral wall of the nasal fossa and the anterior border of the maxillary sinus
true or false. Both the lateral wall of the nasal cavity and the anterior border of the maxillary sinus are composed of dense cortical bone and appear as a radiopaque band.
true
Where is the inverted Y located?
above the maxillary canine
a rounded prominence of bone that extends posterior to the third molar region. Blood vessels and nerves enter the maxilla in this region and supply the posterior teeth
maxillary tuberosity
How does the maxillary tuberosity appear on a radiograph?
on maxillary PA; radiopaque bulge distal to the third molar region
a small hook-like projection of bone extending from the medial pterygoid plate of the sphenoid bone. It is located posterior to the maxillary tuberosity region
hamulus or hamular process
What does the hamulus appear like on a radiograph?
on maxillary PA; radiopaque hook-like projection posterior to maxillary tuberosity area
bony projection of the maxilla that articulates with the zygoma or malar (cheek) bone. composed of dense cortical bone
zygomatic process of maxilla
how does the zygomatic process appear on a radiograph?
maxillary PA; a J- or U- shaped radiopacity located superiorly to the maxillary first molar region
cheek bone, malar or zygomatic bone, articulates with the zygomatic process of the maxilla. Composed of dense cortical bone
zygoma
How does the zygoma appear on a radiograph?
as a diffuse, radiopaque band extending posteriorly from the zygomatic process of the maxilla
What is the largest and strongest bone of the face?
