Radiology Chapter 27

Cortical Bone

outer layer" aka. compact bone; is the dense outer layer of bone. Resists passage of x-ray beam.
APPEARS: RADIOPAQUE

cancellous bone

arranged like lattice"; soft spongy bone located between 2 layers of dense cortical bone.
APPEARS: predominately RADIOLUCENT

process

a marked prominence or projection of bone;
i.e. coronoid process of the mandible

ridge

a linear prominence or projection of bone;
i.e. internal oblique ridge of mandible

spine

a sharp, thornlike projection of bone;
i.e. anterior nasal spine of maxilla

tubercle

a small bump or nodule of bone;
i.e. genial tubercles of mandible

tuberosity

a rounded prominence of bone
i.e. maxillary tuberosity

canal

a tubelike passageway through bone that contains nerves and blood vessels;
i.e. mandibular canal

foramen

an opening or hole in bone that permits the passage of nerves and blood vessels;
i.e. mental foramen of mandible

fossa

a broad shallow scooped-out or depressed area of bone;
i.e. submandibular fossa of mandible

sinus

a hollow space, cavity, or recess in bone;
i.e. the maxillary sinus

septum

a bony wall or partition that divides two spaces or cavities. May be present within fossa or sinus. Bony septum.
APPEARS: RADIOPAQUE
i.e. nasal septum

suture

an immovable joint that represents a line of union between adjoining bones of the skull.
APPEARS: RADIOLUCENT
i.e. median palatine suture of maxilla

incisive foramen

aka.(nasopalatine foramen) an opening or hole in bone located at the midline of the anterior portion of the hard palate directly posterior to maxillary incisors

incisive foramen on a radiograph

appears as a small ovid or round RADIOLUCENT area between roots of maxillary central incisors

superior foramina of the incisive canal

2 tiny openings or holes in bone that are located on the floor of the nasal cavity

superior foramina of the incisive canal on radiograph

appears as 2 small round RADIOLUCENCIES located superior to the apices of maxillary incisors

median palatal suture

the immovable joint between the tow palatine processes of the maxilla. Extends from the alveolar bone between the maxillary centrals to the posterior hard palate.

median palatal suture on a radiograph

appears as a thin RADIOLUCENT line between maxillary centrals

lateral fossa

aka. (canine fossa) is a smooth depressed area of the maxilla located just inferior and medial to the infraorbital foramen between maxillary canine and lateral incisors.

lateral fossa on a radiograph

appears as a RADIOLUCENT area between maxillary canine and lateral incisors

nasal cavity

aka (nasal fossa) is a pear shaped compartment of bone located superior to the maxilla. Is divided by nasal septum

nasal cavity on radiograph

appears as a large RADIOLUCENT area superior to maxillary incisors

nasal septum

a vertical bony wall or partition that divides the nasal cavity into right and left nasal fossa

nasal septum on radiograph

appears as a vertical RADIOPAQUE partition that divides the nasal cavity

floor of the nasal cavity

a bony wall formed by the palatal process of the maxilla and the horizontal portions of the palatine bones. Composed of dense cortical bone.

floor of the nasal cavity on radiograph

appears as a dense RADIOPAQUE band of bone superior to the maxillary incisors

anterior nasal spine

a sharp projection of the maxilla located at the anterior and inferior portion of the nasal cavity

anterior nasal spine on radiograph

appears as a dense RADIOPAQUE V-shape area located at the intersection of the floor of the nasal cavity and nasal septum

inferior nasal conchae

wafer-thin, curved plates of bone that extend from the lateral walls of the nasal cavity conchae means shell shaped or scroll shaped

inferior nasal conchae on radiograph

appears as a diffuse RADIOPAQUE mass or projection within the nasal cavity

maxillary sinus

paired cavities or compartments of bone located within the maxilla. Superior to maxillary premolar/molar region.

maxillary sinus on radiograph

appears as a RADIOLUCENT area located superior to the apices of maxillary premolars and molars. Floor of maxillary sinus composed of dense cortical bone and appears as RADIOPAQUE line.

septa within Maxillary Sinus

(septa is plural for septum) within maxillary sinus. Bony walls or partitions that appear to divide the maxillary sinus into compartments

septa within Maxillary Sinus on radiograph

appears as RADIOPAQUE lines within maxillary sinus

nutrient canals

within maxillary sinus; tiny; tubelike passageways through bone, which contain blood vessels and nerves that supply maxillary teeth and interdental areas

nutrient canals on radiograph

appears as a narrow RADIOLUCENT band bound by 2 RADIOPAQUE lines

inverted Y

the intersection of the maxillary sinus and the nasal cavity as viewed on a dental image

inverted Y on a radiograph

appears as a RADIOPAQUE upside down Y formed by the intersection of the lateral wall of the nasal fossa and anterior border of maxillary sinus superior to the maxillary canine

maxillary tuberosity

a rounded prominence of bone that extends posterior to the third molar region

maxillary tuberosity on radiograph

appears as a RADIOPAQUE bulge distal to the third molar region

hamulus

aka. (hamular process) small, hooklike projection of bone extending from the medial pterygoid plate of the sphenoid bone. Posterior to the maxillary tuberosity.

hamulus on radiograph

appears as a RADIOPAQUE hooklike projection posterior to maxillary tuberosity area

zygomatic process of maxilla

a bony projection of the maxilla that articulates with the zygoma or malar bone. Composed of dense cortical bone.

zygomatic process of maxilla on radiograph

appears as a J or U shaped RADIOPACITY located superior to the maxillary 1st molar region

zygoma

or "cheek bone" aka. (malar bone or zygomatic bone) articulates with zygomatic process of maxilla. Composed of dense cortical bone.

zygoma on radiograph

appears as a diffuse RADIOPAQUE band extending posteriorly from zygomatic process of maxilla

ramus

the ramus is the vertical portion of the mandible that is found posterior to the third molar. Has 2 rami one on each side.

body of mandible

horizontal, U-shaped portion that extends from ramus to ramus

alveolar process

portion of the mandible that encases the teeth and supports teeth

genial tubercles

tiny bumps of bone that serve as attachment sites for genioglossus and genohyoid muscles. Located on lingual aspect of mandible.

genial tubercles on radiograph

appears as a small RADIOLUCENT dot located inferior to the apices of mandibular incisors

nutrient canals (mandible)

tubelike passageways through bone that contains nerve and blood vessels that supply teeth. Inderdental nutrient canals most often seen in anterior mandible, region that typically has thin bone.

nutrient canals (mandible) on radiograph

appears as vertical RADIOLUCENT lines readily seen in areas of thin bone. Maybe more prominent in edentulous mandible.

mental ridge

a linear prominence of cortical bone located on the external surface of the anterior portion of the mandible. Extends from premolar region to the midline and stops slightly upward

mental ridge on radiograph

appears as a thick RADIOPAQUE band that extends from premolar to incisor region

mental fossa

a scooped-out depressed area of bone located on external surface of the anterior mandible. Above mental ridge in mandible incisor region.

mental fossa on radiograph

appears as a RADIOLUCENT area above the mental ridge

mental foramen

an opening or hole in bone located on external surface of the mandible in region of mandible premolars

mental foramen on radiograph

appears as a small ovoid or round RADIOLUCENT area located in apical region of mandibular premolars.

mylohyoid ridge

a linear prominence of bone located on the internal surface of the mandible. Extends from molar region downward and forward toward lower border of mandibular symphysis

mylohyoid ridge on radiograph

appears as a dense RADIOPAQUE band that extends downward and forward from the molar region. Usually prominently in molar region

Mandibular canal

tubelike passageway through bone that travels the length of the mandible. Extends from mandibular foramen to mental foramen.

mandibular canal on radiograph

appears as a RADIOLUCENT band it's outlined by two thin RADIOPAQUE lines that represent the cortical walls of the canal. Canal appears below or superimposed over apices of mandibular molars.

internal oblique ridge

aka (. internal oblique line) a linear prominence of bone located on the internal surface of the mandible that extends downward and forward from the ramus. May end in 3rd molar region or extend into the mylohyoid ridge.

internal oblique ridge on radiograph

appears as a RADIOPAQUE band that extends downward and forward from the ramus. The internal and external oblique ridges may superimpose each other. Internal ridge may appear external and vice versa.

external oblique ridge

aka (external oblique line) a linear prominence of bone located on external surface of body of mandible. Anterior border of ramus ends the external oblique ridge.

external oblique ridge on radiograph

appears as RADIOPAQUE band extending downward and forward from anterior border of ramus of mandible. Typically ends in the mandibular 3rd molar region.

submandibular fossa

aka (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. The submandibular salivary gland found in the submandibular fossa

submandibular fossa on radiograph

appears as a RADIOLUCENT area in the molar region below the mylohyoid ridge. Few bony trabeculae are usually seen in the region.

coronoid process

a marked prominence of bone on the anterior ramus of the mandible. Serves as attachment site for one of the muscles of mastication.

coronoid process on radiograph

not seen on mandibular PA but dose appear on a maxillary molar PA.
appears as a triangle RADIOPACITY superimposed over or inferior to the maxillary tuberosity region.

enamel on radiograph

appears RADIOPAQUE

dentin on radiograph

appears RADIOPAQUE

DEJ on radiograph

appears VERY RADIOPAQUE

pulp cavity on radiograph

appears RADIOLUCENT

alveolar bone on radiograph

appears RADIOPAQUE

lamina dura

the wall of the tooth socket that surrounds the root of the tooth. Dense cortical bone.

lamina dura on radiograph

appears dense RADIOPAQUE line around root of a tooth

alveolar crest

most coronal portion of alveolar bone found between teeth. Dense cortical bone and is continuous with lamina dura.

alveolar crest on radiograph

appears RADIOPAQUE typically 1.5 to 2.0mm below junction of crown and the root surfaces (CEJ)

PDL

space between root of tooth and lamina dura

PDL on radiograph

appears as a thin RADIOLUCENT line around root of the tooth

anterior region of alveolar bone

normal alveolar crest located in anterior region appears pointed and sharp between teeth

anterior region of alveolar bone on radiograph

appears as dense RADIOPAQUE line in anterior region

posterior region of alveolar bone

normal; appears flat and smooth between teeth

posterior region of alveolar bone on radiograph

appears less dense and less RADIOPAQUE than in anterior region