RAD: Ch. 28 - Normal Anatomy and Landmarks

What are the two types of bone distinguished in dental radiography?

Cortical bone and cancellous bone.

What is cortical bone?

Cortical bone is the dense outer layer of bone that provides strength and support.

What is cancellous bone?

Cancellous bone is the spongy inner layer of bone that contains marrow and is lighter than cortical bone.

What are prominences in bone anatomy?

Prominences are raised areas or projections on the surface of bones.

What are spaces in bone anatomy?

Spaces are openings or cavities within the bone structure.

What are depressions in bone anatomy?

Depressions are indentations or hollowed areas on the surface of bones.

How are the normal anatomic landmarks of the maxilla identified on dental images?

They are identified based on their radiolucent or radiopaque characteristics.

What does radiolucent mean in dental imaging?

Radiolucent refers to areas that appear dark on radiographs, indicating less dense structures.

What does radiopaque mean in dental imaging?

Radiopaque refers to areas that appear light on radiographs, indicating denser structures.

What is the purpose of reviewing the anatomy of the maxilla and mandible?

To review the normal anatomy of the maxilla and mandible as viewed on the skull and describe the normal anatomic landmarks seen on intraoral images.

What is a process in bone anatomy?

A marked prominence or projection.

What is a ridge in bone anatomy?

A linear prominence or projection.

What is a spine in bone anatomy?

A sharp, thornlike projection.

What is a tubercle?

A small bump or nodule.

What is a tuberosity?

A rounded prominence.

What is a canal in bone anatomy?

A tubelike passageway through bone that contains nerves and blood vessels.

What is a foramen?

An opening or hole that permits the passage of nerves and blood vessels.

What is a fossa?

A broad, shallow, scooped-out, or depressed area.

What is a sinus in bone anatomy?

A hollow space, cavity, or recess.

What is the incisive foramen?

An opening located at the midline of the anterior portion of the hard palate, directly posterior to the maxillary central incisors.

What does the incisive foramen appear as on an image?

A small ovoid or round radiolucent area located between the roots of the maxillary central incisors.

What is the median palatal suture?

An immovable joint between the two palatine processes of the maxilla.

How does the median palatal suture appear on an image?

As a thin radiolucent line between the maxillary central incisors.

What is the nasal cavity?

A pear-shaped compartment of bone located superior to the maxilla.

What does the nasal cavity appear as on an image?

A large radiolucent area above the maxillary incisors.

What is the maxillary sinus?

Paired cavities located within the maxilla, above the maxillary premolar and molar teeth.

What does the maxillary sinus appear as on an image?

A radiolucent area located above the apices of the maxillary premolars and molars.

What is the inverted Y in dental anatomy?

The intersection of the maxillary sinus and the nasal cavity.

What does the inverted Y appear as on an image?

A radiopaque upside-down Y located above the maxillary canine.

What is the zygomatic process of the maxilla?

A bony projection of the maxilla that articulates with the zygoma or malar (cheek) bone.

How does the zygomatic process appear on an image?

As a J- or U-shaped radiopacity located superior to the maxillary first molar region.

What is the anterior nasal spine?

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

What does the anterior nasal spine appear as on an image?

A V-shaped radiopaque area located at the intersection of the floor of the nasal cavity and the nasal septum.

What are the inferior nasal conchae?

Wafer-thin, curved plates of bone that extend from the lateral walls of the nasal cavity.

How do the inferior nasal conchae appear on an image?

As a diffuse radiopaque mass or projection within the nasal cavity.

What is the largest and strongest bone of the face?

The mandible

What are the three main parts of the mandible?

Ramus, Body, Alveolar process

What is the ramus of the mandible?

The vertical portion found posterior to the third molar

What is the body of the mandible?

The horizontal U-shaped portion from ramus to ramus

What does the alveolar process do?

Encases and supports the teeth

What are genial tubercles?

Tiny bumps of bone on the lingual aspect of the mandible

How do genial tubercles appear on dental images?

As a ring-shaped radiopacity below the apices of the mandibular incisors

What is the lingual foramen?

A tiny opening or hole in bone located on the internal surface of the mandible

How does the lingual foramen appear on dental images?

As a small radiolucent dot inferior to the apices of the mandibular incisors

What are nutrient canals?

Tubelike passageways through bone containing nerves and blood vessels that supply the teeth

How do nutrient canals appear on dental images?

As vertical radiolucent lines readily seen in areas of thin bone

What is the mental ridge?

A linear prominence of cortical bone located on the external surface of the anterior portion of the mandible

How does the mental ridge appear on dental images?

As a thick radiopaque band that extends from the premolar region to the incisor region

What is the mental fossa?

A scooped-out, depressed area of bone located on the external surface of the anterior mandible

How does the mental fossa appear on dental images?

As a radiolucent area above the mental ridge

What is the mental foramen?

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

How does the mental foramen appear on dental images?

As a small ovoid or round radiolucent area located in the apical region of the mandibular premolars

What is the mandibular canal?

A tubelike passageway through bone that travels the length of the mandible

What does the mandibular canal house?

The inferior alveolar nerve and blood vessels

How does the mandibular canal appear on dental images?

As a radiolucent band outlined by two thin radiopaque lines

What is the mylohyoid ridge?

A linear prominence of bone located on the internal surface of the mandible

How does the mylohyoid ridge appear on dental images?

As a dense radiopaque band extending downward and forward from the molar region

What is the external oblique ridge?

A linear prominence of bone located on the external surface of the body of the mandible

How does the external oblique ridge appear on dental images?

As a radiopaque band extending downward and forward from the anterior border of the ramus

What is the coronoid process?

A marked prominence of bone on the anterior ramus of the mandible

How does the coronoid process appear on dental images?

As a triangular radiopacity superimposed over or inferior to the maxillary tuberosity region

What is enamel in tooth structure?

The outermost radiopaque layer of the crown of a tooth

What is dentin?

The material that comprises most of the tooth structure, less radiopaque than enamel

What is the dentino-enamel junction (DEJ)?

The junction between dentin and enamel

What is the pulp cavity?

A pulp chamber and pulp canals within the tooth

What is the lamina dura?

The wall of the tooth socket made of dense cortical bone

How does the lamina dura appear on dental images?

As a dense radiopaque line that surrounds the root of a tooth

What is the alveolar crest?

The most coronal portion of the alveolar bone found between teeth

How does the alveolar crest appear on dental images?

As a radiopaque line typically 1.5 to 2.0 mm below the cementoenamel junction

What is the periodontal ligament space?

The space between the root of the tooth and the lamina dura

How does the periodontal ligament space appear on dental images?

As a thin radiolucent line around the root of a tooth

At what age do primary teeth begin to erupt?

At the age of 6 months

How many primary teeth should be erupted by the age of 3?

All 20 primary teeth

What is primary dentition?

Also known as deciduous dentition, comprised of 10 maxillary and 10 mandibular teeth

What is mixed dentition?

The presence of both primary and permanent teeth between the ages of 6 and 12