Anatomic Landmarks Flashcards
2 types of bone?
Cortical bone
Cancellous bone
The term cortical is derived from the Latin word cortex and means?
outer layer
Also referred to as compact bone.
Cortical bone
The dense outer layer of bone.
Cortical bone
- Cortical bone resists the passage of the xray beam and appears ___________ on a dental image.
- The _______________ is composed of cortical bone.
- radiopaque
- inferior border of the mandible
The term cancellous is also derived from Latin and means _____________?
“arranged like a lattice.”
The soft, spongy bone located between two layers of dense cortical bone.
Cancellous bone
Composed of numerous bony trabeculae that form a lattice-like network of intercommunicating spaces filled with bone marrow.
Cancellous bone
The _________, actual pieces of bone, resist the passage of the x-ray beam and appear _______; in contrast, the _________ permit the passage of the x-ray beam and appear _______.
- trabeculae; radiopaque
- marrow spaces; radiolucent
The LARGER the trabeculations, the more _________ the area of cancellous bone appears.
radiolucent
Cancellous bone appears predominantly ________.
radiolucent
Composed of dense cortical bone and appear radiopaque on dental images
Prominences of the bone.
5 prominences of the bone?
process
ridge
spine
tubercle
tuberosity
A marked prominence or projection of bone.
Process
A linear prominence or projection of bone
Ridge
A sharp, thorn-like projection of bone.
Spine
A small bump or nodule of bone.
Tubercle
A rounded prominence of bone.
Tuberosity
Do not resist the passage of the x-ray beam and appear radiolucent on dental images.
Spaces and depressions in bone
4 types of spaces and depressions in bone
canal
foramen
fossa
sinus
A tubelike passageway through bone that contains nerves and blood.
Canal
An opening or hole in bone that permits the passage of nerves and blood vessels.
Foramen
A broad, shallow, scooped-out or depressed area of bone.
Fossa
A hollow space, cavity, or recess in bone.
Sinus
A bony wall or partition that divides two spaces or cavities. May be present within the space of a fossa or sinus.
Septum
A bony septum appears _________, in contrast to a space or cavity, which appears ________.
radiopaque; radiolucent
An immovable joint that represents a line of union between adjoining bones of the skull.
Sutures
Sutures are only found in the?
skull
A suture appears as a ___________.
thin radiolucent line
Also known as
the nasopalatine foramen.
Incisive foramen
An opening or hole in bone located at the midline of the anterior portion of the hard palate directly posterior to the maxillary central incisors.
Incisive foramen
The _____________ nerve exits the maxilla through the incisive foramen.
nasopalatine nerve
Appears as a small, ovoid or round radiolucent area located between the roots of the maxillary central incisors
Incisive foramen
Are two tiny openings or holes in bone that are located on the floor of the nasal cavity
Superior foramina of incisive canal
The openings of two small canals that extend downward and medially from the floor
of the nasal cavity
Superior foramina of incisive canal
These superior foramina join together to form the _________ and share a common exit, the ________
incisive canal
incisive foramen
The nasopalatine nerve enters the maxilla through the ________, travels through the _________, and exits at the __________.
- superior foramina
- incisive canal
- incisive foramen.
Appear as two small, round radiolucencies located superior to the apices of the maxillary central incisors.
Superior foramina of incisive canal
A suture is the immovable joint between the two palatine processes of the maxilla.
Median Palatal Suture
Extends from the alveolar bone between the maxillary central incisors to the posterior hard palate.
Median Palatal Suture
- Appears as a thin
radiolucent line between the maxillary central incisors. - Is bounded on both sides by dense cortical bone that appears radiopaque.
- As it fuses with age, it may become less distinct on a dental image.
Median Palatal Suture
A smooth, depressed area of the maxilla located just inferior and medial to the infraorbital foramen between maxillary canine and lateral incisors.
Lateral fossa
Appears as a radiolucent area between the maxillary canine and lateral incisor.
Lateral fossa
A pear-shaped compartment of bone
located superior to the maxilla.
Nasal cavity
The inferior portion, or floor, of the nasal cavity is formed by the __________ of the maxilla and the horizontal portions of ____________.
- palatal processes
- palatine bones
The lateral walls of the nasal cavity
are formed by the _________ and the _________.
ethmoid bone
maxillae
The nasal cavity is divided by a bony partition, or wall, called the _________.
nasal septum
Appears as a large, radiolucent area superior to the maxillary incisors.
Nasal cavity
The nasal cavity is also known as?
nasal fossa
A vertical bony wall or partition that divides the nasal cavity into the right and left nasal fossae.
Nasal septum.
The nasal septum is formed by cartilage and two bones which are?
the vomer and a portion of the ethmoid bone.
Appears as a vertical radiopaque partition that divides the nasal cavity. May be superimposed over the median palatal suture.
Nasal septum
A bony wall formed by the palatal processes of the maxilla and the horizontal portions of palatine bones.
Floor of the nasal cavity
The floor is composed of dense cortical bone and defines the __________ of the nasal cavity.
inferior border
Appears as a dense radiopaque band of bone superior to the maxillary incisors.
Floor of the nasal cavity
A sharp projection of the maxilla located at the anterior and
inferior portion of the nasal cavity.
Anterior nasal spine
Appears as a V-shaped radiopaque area located at the intersection of the floor of the nasal cavity and the nasal septum.
Anterior nasal spine
Are wafer-thin, curved plates of bone that extend from the lateral walls of the nasal cavity.
Inferior nasal conchae
Are seen in the lower lateral portions of the nasal cavity.
Inferior nasal conchae
The term concha is derived from Latin and means ?
“shell shaped” or “scroll shaped.”
Appear as diffuse radiopaque masses or projections within the nasal cavity.
Inferior nasal conchae
Are paired cavities or compartments of bone located within the maxilla.
Maxillary sinus
Maxillary sinuses are located superior to maxillary _____ and ____ teeth. Rarely does the maxillary sinus extend anteriorly beyond the ______.
- premolar and molar
- canines
TRUE OR FALSE
At birth, the maxillary sinus is the size of a small pea. With growth, the maxillary sinus expands and eventually occupies a large portion of the maxilla.
TRUE
The maxillary sinus may extend to include ? (3)
- interdental bone
- molar furcation areas
- maxillary tuberosity region
Appears as a radiolucent area located superior to the apices of maxillary premolars and molars.
Maxillary sinus
The ______ of the maxillary sinus is composed of dense cortical bone and appears as a __________ line.
floor
radiopaque
May be seen within the maxillary sinus. Are bony walls or partitions that appear to divide the maxillary sinus into compartments.
Septa Within Maxillary Sinus
Appear as radiopaque lines within the maxillary sinus
Septa Within Maxillary Sinus
May be seen within maxillary sinuses. These are tiny, tubelike passageways through bone, which contain blood vessels and nerves that supply maxillary teeth and interdental areas.
Nutrient canals within maxillary sinus
Appears as a narrow radiolucent band bounded by two thin radiopaque lines. The radiopaque lines represent the cortical bone that makes up the walls of the canal.
Nutrient canals within maxillary sinus
Refers to the intersection of the maxillary sinus and the nasal cavity as viewed on a dental image.
Inverted Y
Appears as a radiopaque upside-down Y formed by the intersection of the lateral wall of the nasal fossa and the anterior border of the maxillary sinus.
Inverted Y
The inverted Y is located superior to 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 posterior teeth
Maxillary tuberosity
Appears as a radiopaque bulge distal to the third molar region.
Maxillary tuberosity
A small, hooklike projection of bone extending from the medial pterygoid plate of the sphenoid bone. Located posterior to the maxillary tuberosity region.
Hamulus
Appears as a radiopaque hooklike projection posterior to the maxillary tuberosity area.
Hamulus
A bony projection of the maxilla that articulates with the zygoma, or malar bone. It is composed of dense cortical bone.
Zygomatic process of the maxilla
Appears as a J-shaped or U-shaped radiopacity located superior to the maxillary first molar region.
Zygomatic process of the maxilla
the “cheekbone”
Zygoma
Referred to as the malar bone
Zygoma
Articulates with the zygomatic process of the maxilla. It is composed of dense cortical bone.
Zygoma
Appears as a diffuse radiopaque band extending posteriorly from the zygomatic process of the maxilla
Zygoma
The term mandible comes from Latin mandibula meaning _______.
jaw bone
The horseshoe-shaped bone that forms the lower jaw bone. It is the largest and strongest bone of the face.
Mandible
The vertical portion of the mandible that is found posterior to the third molar.
Ramus
How many ramus does the mandible have?
Two (on each side)
The horizontal, U-shaped portion that extends from ramus to ramus.
Body of the mandible
The corner portion formed by the junction of the posterior and lower borders of the ramus.
Angle of the mandible
The corner portion formed by the junction of the posterior and lower borders of the ramus.
Angle of mandible
The portion of the mandible that encases and supports teeth
Alveolar process
The mandible is a single bone that is divided into the what sections? (4)
- ramus
- body
- angle
- alveolar process
Are tiny bumps of bone that serve as attachment sites for the genioglossus and geniohyoid muscles.
Genial tubercles
Genial tubercles are located on the _____ aspect of the mandible.
lingual
Appear as a ring-shaped radiopacity inferior to the apices of the mandibular incisors.
Genial tubercles
A tiny opening or hole in bone located on the internal surface of the mandible.
Lingual foramen
- Appears as a small, radiolucent dot located inferior to the apices of the mandibular incisors.
- It is surrounded by genial tubercles, which appear as a ___________.
- Lingual foramen
- radiopaque ring
The lingual foramen is located near the midline and is surrounded by _____________.
genial tubercles
Are tubelike passageways through bone that contain nerves and blood vessels that supply teeth.
Nutrient canals
Are most often seen in the anterior mandible, a region that typically has thin bone.
Interdental nutrient canals
Appear as vertical radiolucent bands.
Are readily seen in areas of thin bone. In the edentulous mandible, they may be more prominent.
Nutrient canals
A linear prominence of cortical bone located on the external surface of the anterior portion of the mandible.
Mental ridge
The mental ridge extends from the __________ region to the midline and slopes slightly upward.
premolar
Appears as a thick radiopaque band that extends from the premolar region to the incisor region.
Mental ridge
On a dental image, the mental ridge often appears ____________ over ___________ teeth.
superimposed; mandibular anterior
A scooped-out, depressed area of bone located on the external surface of the anterior mandible.
Mental fossa
The mental fossa is located above the mental ridge in the ______________ region.
mandibular incisor
Appears as a radiolucent area above the mental ridge.
Mental fossa
On a dental image, the appearance of the mental fossa varies and is determined by the thickness of the bone in the ________ region of the mandible.
anterior
An opening or hole in bone located on the external surface of the mandible in the region of the mandibular premolars.
Mental foramen
Blood vessels and nerves that supply the lower lip exit through the _______________-.
mental foramen
Appears as a small, ovoid or round radiolucent area located in the apical region of the mandibular premolars.
Mental foramen
The mental foramen may be misdiagnosed as a PERIAPICAL LESION (________, _______, or ______) because of its apical location.
periapical cyst, granuloma, or abscess
A tubelike passageway through bone that travels the length of the mandible.
Mandibular canal
The mandibular canal extends from the ____________ to the ____________ and houses the ___________ and blood vessels.
- mandibular foramen; mental foramen
- inferior alveolar nerve
Appears as a radiolucent band. Appears below or superimposed over the apices of the mandibular molar teeth.
Mandibular canal
The mylohyoid ridge is also known as?
internal oblique ridge
A linear prominence of bone located on the internal surface of the mandible.
Mylohyoid ridge
The mylohyoid ridge extends from the ________ region downward and forward to the __________ area.
third molar; second premolar
Appears as a dense radiopaque band that extends downward and forward from the third molar region at the level of the apices of the posterior teeth.
Mylohyoid ridge
The mylohyoid ridge usually appears most prominently in the _______ region and may be superimposed over the roots of the mandibular teeth.
molar
The external oblique ridge is also known as?
external oblique line
A linear prominence of bone located on the external surface of the body of the mandible.
External oblique ridge
The ________ border of the ramus ends in the external oblique ridge.
anterior
Appears as a radiopaque band extending downward and forward from the anterior border of the ramus of the mandible
External oblique ridge
The external oblique ridge typically ends in the mandibular ________ region.
third molar
Extends vertically downward from the coronoid process to the external oblique ridge.
Anterior border of the ramus
May be seen as a slightly radiopaque vertical band posterior to the maxillary and mandibular molars.
Anterior border of the ramus
The submandibular fossa is also known as? (2)
Mandibular fossa or submaxillary fossa
A scooped-out, depressed area of bone located on the internal surface of the mandible inferior to the mylohyoid ridge.
Submandibular fossa
The ___________ is found in the submandibular fossa.
Submandibular salivary gland
Appears as a radiolucent area in the molar region below the mylohyoid ridge. Few bony trabeculae are usually seen in this region.
Submandibular fossa
A marked prominence of bone on the anterior ramus of the mandible. It serves as an attachment site for one of the muscles of mastication.
Coronoid process
Not seen on a mandibular periapical image but may appear on a maxillary molar periapical image.
Appears as a triangular radiopacity superimposed over, or inferior to, the maxillary tuberosity region.
Coronoid process
The densest structure found in the human body.
Enamel
The outermost radiopaque layer of the crown of a tooth.
Enamel
Found beneath the enamel layer of a tooth and surrounds the pulp cavity. It appears radiopaque and makes up the majority of the tooth structure.
Dentin
Which is more radiopaque? Enamel or dentin?
Enamel
The junction between the dentin and the enamel of a tooth.
- Dentino-enamel junction (DEJ)
The DEJ appears as a line where the _______ (very radiopaque) meets the ________ (less radiopaque).
enamel; dentin
The pulp cavity consists of (2)?
Pulp chamber
Pulp canals
It contains blood vessels, nerves, and lymphatics and appears relatively radiolucent on a dental image.
Pulp cavity
Pulp cavity is larger in? (children / adults?)
Children
Pulp cavity decreases in size with age due to the formation of ______________.
Secondary dentin
Serves as the supporting structure for teeth. It is the bone of the maxilla and the mandible that supports and encases the roots of teeth. It is composed of dense cortical bone and cancellous bone.
Alveolar process / alveolar bone
The anatomic landmarks of the alveolar process include (3)?
lamina dura, the alveolar crest, and the periodontal ligament space.
The wall of the tooth socket that surrounds the root of a tooth. It is made up of dense cortical bone.
Lamina dura
Appears as a dense radiopaque line that surrounds the root of a tooth.
Lamina dura
The most coronal portion of alveolar bone found between teeth. It is made up of dense cortical bone and is continuous with the lamina dura.
Alveolar crest
Appears radiopaque and is typically located 1.5 to 2.0 mm below the junction of the crown and the root surfaces (the cementoenamel junction).
Alveolar crest
The space between the root of the tooth and the lamina dura. It contains connective tissue fibers, blood vessels, and lymphatics
Periodontal Ligament Space
Appears as a thin radiolucent line around the root of a tooth. In the healthy periodontium, it appears as a continuous radiolucent line of uniform thickness.
Periodontal Ligament Space
- Healthy alveolar crest located in the anterior region appears ___________ between teeth.
- The alveolar crest appears as a dense ________ line in the anterior region.
- pointed and sharp
- radiopaque
- Healthy alveolar crest located in the posterior region appears at and ______ between teeth.
- The alveolar crest located in the posterior region tends to appear __________ and __________ than the alveolar crest seen in the anterior region.
- smooth
- less dense; less radiopaque
