Transcript Normal Anatomy

Chapter 27
Normal Anatomy:
Intraoral Images
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
Dental Radiography
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Questions
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What is the difference between cortical and
cancellous bone?
What normal anatomic landmarks of the maxilla
and mandible are apparent on dental
radiographs?
What is the radiographic appearance of tooth
anatomy?
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Dental Radiography
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Chapter 27 Reading
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Iannucci & Howerton (pp. 325-344)
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Dental Radiography
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Chapter 27 Outline
Normal Anatomy: Intraoral Films
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Definitions of general terms
 Normal anatomic landmarks
 Normal tooth anatomy
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Introduction
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Iannucci & Howerton (pp. 326)
Purpose
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To review the normal anatomy of the maxilla and
mandible as viewed on the skull
To describe the normal anatomic landmarks seen
on intraoral radiographs
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Definitions of General Terms
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Types of bone
Prominences of bone
Spaces and depressions in bone
Miscellaneous terms
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Types of Bone
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Cortical bone
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Iannucci & Howerton (pp. 326-327) (Figs. 27-1
through 27-3)
The dense outer layer of bone
Appears radiopaque on a radiograph
Cancellous bone
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The soft, spongy bone located between two layers
of dense cortical bone
Appears primarily radiolucent
• Trabeculae appear radiopaque, marrow spaces appear
radiolucent
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Prominences of Bone
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Iannucci & Howerton (pp. 326-328) (Figs. 27-4
through 27-8)
Process: marked prominence or projection
Ridge: linear prominence or projection
Spine: sharp, thornlike projection
Tubercle: small bump or nodule
Tuberosity: rounded prominence
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Spaces and Depressions in Bone
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Iannucci & Howerton (pp. 328-330) (Figs. 27-9,
27-10)
Canal – tubelike passageway through bone
that contains nerves and blood vessels
Foramen – opening or hole that permits the
passage of nerves and blood vessels
Fossa – broad, shallow, scooped-out, or
depressed area
Sinus – hollow space, cavity, or recess
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Miscellaneous Terms
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Septum
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Iannucci & Howerton (pp. 327-328) (Fig. 27-11)
A bony wall or partition that divides two spaces or
cavities
Radiopaque
Suture
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An immovable joint representing a line of union
between adjoining bones of the skull
A thin radiolucent line
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Normal Anatomic Landmarks
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Iannucci & Howerton (pp. 328)
Bony landmarks of the maxilla
Bony landmarks of the mandible
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Bony Landmarks of the Maxilla
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The upper jaw is composed of two paired
bones, the maxillae.
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Iannucci & Howerton (pp. 328-329) (Fig. 27-12)
The paired maxillae meet at the midline of the
face.
Forms the
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Floor of the orbit of the eye
Sides and floor of the nasal cavities
Hard palate
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Bony Landmarks of the Maxilla
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Incisive foramen
Superior foramina of the incisive canal
Median palatal suture
Lateral fossa
Nasal cavity
Nasal septum
Floor of the nasal cavity
Anterior nasal spine
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Bony Landmarks of the Maxilla
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Inferior nasal conchae
Maxillary sinus
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Septa within the maxillary sinus
Nutrient canals within the maxillary sinus
Inverted Y
Maxillary tuberosity
Hamulus
Zygomatic process of the maxilla
Zygoma
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Incisive Foramen
(Nasopalatine Foramen)
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Description
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Iannucci & Howerton (pp. 329-330) (Fig. 27-13)
An opening or hole in bone that is located at the
midline of the anterior portion of the hard palate
directly posterior to the maxillary central incisors
Appearance
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A small ovoid or round radiolucent area located
between the roots of the maxillary central incisors
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Superior Foramina of the
Incisive Canal
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Description
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Iannucci & Howerton (pp. 329-330) (Fig. 27-14)
Two tiny openings or holes in bone that are
located on the floor of the nasal cavity
Join together to form the incisive canal
Appearance
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Two small round radiolucencies located superior
to the apices of the maxillary central incisors
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Median Palatal Suture
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Description
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Iannucci & Howerton (p. 330) (Fig. 27-15)
The immovable joint between the two palatine
processes of the maxilla
Appearance
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A thin radiolucent line between the maxillary
central incisors
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Lateral Fossa
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Description
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Iannucci & Howerton (pp. 330-331) (Fig. 27-16)
A smooth, depressed area of the maxilla located
just inferior and medial to the infraorbital foramen
between the canine and lateral incisors
Appearance
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A radiolucent area between the maxillary canine
and lateral incisors
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Nasal Cavity
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Iannucci & Howerton (p. 331) (Fig. 27-17)
Description
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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 portions of the palatine
bones.
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Appearance
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A large radiolucent area above the maxillary
incisors
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Nasal Septum
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Description
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Iannucci & Howerton (p. 331) (Fig. 27-18)
A vertical bony wall or partition that divides the
nasal cavity into the right and left nasal fossae
Formed by the vomer and a portion of the ethmoid
bone and cartilage
Appearance
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A vertical radiopaque partition that divides the
nasal cavity
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Floor of the Nasal Cavity
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Description
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Iannucci & Howerton (p. 332) (Fig. 27-19)
A bony wall formed by the palatal processes of the
maxilla and the horizontal portions of the palatine
bones
Appearance
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A dense radiopaque band of bone above the
maxillary incisors
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Anterior Nasal Spine
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Description
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Iannucci & Howerton (p. 332) (Fig. 27-20)
A sharp projection of the maxilla located at the
anterior and inferior portion of the nasal cavity
Appearance
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A V-shaped radiopaque area located at the
intersection of the floor of the nasal cavity and the
nasal septum
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Inferior Nasal Conchae
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Description
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Iannucci & Howerton (pp. 332-333) (Fig. 27-21)
Wafer-thin, curved plates of bone that extend from
the lateral walls of the nasal cavity
Conchae means shell-shaped or scroll-shaped.
Appearance
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A diffuse radiopaque mass or projection within the
nasal cavity
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Maxillary Sinus
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Description
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Iannucci & Howerton (pp. 332-333) (Figs. 27-22,
27-23)
Paired cavities or compartments of bone located
within the maxilla
Located above the maxillary premolar and molar
teeth
Appearance
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A radiolucent area located above the apices of the
maxillary premolars and molars
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Septa within the Maxillary Sinus
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Description
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Iannucci & Howerton (pp. 332-333) (Figs. 27-24,
27-25)
Bony walls or partitions that appear to divide the
maxillary sinus into compartments
Appearance
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Radiopaque lines within the maxillary sinus
 Presence and number vary depending on the
anatomy of the individual.
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Nutrient Canals within the
Maxillary Sinus
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Description
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Iannucci & Howerton (p. 334) (Fig. 27-26)
Tiny, tubelike passageways through bone that
contain blood vessels and nerves
Appearance
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A narrow radiolucent band bounded by two thin
radiopaque lines
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Inverted Y
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Description
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Iannucci & Howerton (p. 334) (Fig. 27-27)
The intersection of the maxillary sinus and the
nasal cavity
Appearance
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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
Located above the maxillary canine
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Maxillary Tuberosity
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Description
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Iannucci & Howerton (p. 334) (Fig. 27-28)
A rounded prominence of bone that extends
posterior to the third molar region
Appearance
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A radiopaque bulge distal to the third molar region
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Hamulus
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Description
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Iannucci & Howerton (pp. 334-335) (Fig. 27-29)
A small hooklike projection of bone extending from
the medial pterygoid plate of the sphenoid bone
Appearance
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A radiopaque hooklike projection posterior to the
maxillary tuberosity area
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Zygomatic Process of the Maxilla
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Description
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Iannucci & Howerton (pp. 334-335) (Figs. 27-30,
27-31)
A bony projection of the maxilla that articulates
with the zygoma or malar (cheek) bone
Appearance
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A J- or U-shaped radiopacity located superior to
the maxillary first molar region
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Zygoma
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Description
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Iannucci & Howerton (pp. 335-336) (Figs. 27-32,
27-33)
Articulates with the zygomatic process of the
maxilla
Appearance
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A diffuse, radiopaque band extending posteriorly
from the zygomatic process of the maxilla
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Bony Landmarks of the Mandible
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Iannucci & Howerton (pp. 335-336) (Fig. 27-34)
The largest and strongest bone of the face
Divided into three main parts
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Ramus
• Vertical portion found posterior to the third molar
 Body
• Horizontal U-shaped portion from ramus to ramus
 Alveolar process
• Encases and supports the teeth
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Bony Landmarks of the Mandible
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Iannucci & Howerton (pp. 335-340)
Genial tubercles
Lingual foramen
Nutrient canals
Mental ridge
Mental fossa
Mental foramen
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Bony Landmarks of the Mandible
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Mylohyoid ridge
Mandibular canal
Internal oblique ridge
External oblique ridge
Submandibular fossa
Coronoid process
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Genial Tubercles
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Description
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Iannucci & Howerton (pp. 335-336) (Fig. 27-35)
Tiny bumps of bone on the lingual aspect of the
mandible
Attachment sites for genioglossus and geniohyoid
muscles
Appearance
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A ring-shaped radiopacity below the apices of the
mandibular incisors
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Lingual Foramen
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Description
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Iannucci & Howerton (p. 336) (Fig. 27-36)
A tiny opening or hole in bone located on the
internal surface of the mandible
Appearance
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A small radiolucent dot inferior to the apices of the
mandibular incisors
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Nutrient Canals
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Description
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Iannucci & Howerton (pp. 336-337) (Fig. 27-37)
Tubelike passageways through bone containing
nerves and blood vessels that supply the teeth
Most often seen in anterior mandible
Appearance
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Vertical radiolucent lines readily seen in areas of
thin bone
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Mental Ridge
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Description
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Iannucci & Howerton (p. 337) (Fig. 27-38)
A linear prominence of cortical bone located on
the external surface of the anterior portion of the
mandible
Appearance
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A thick radiopaque band that extends from the
premolar region to the incisor region
Often appears superimposed over the mandibular
anterior teeth
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38
Mental Fossa
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Description
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Iannucci & Howerton (pp. 337-338) (Fig. 27-39)
A scooped-out, depressed area of bone located
on the external surface of the anterior mandible
Appearance
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A radiolucent area above the mental ridge
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Mental Foramen
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Description
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Iannucci & Howerton (pp. 337-338) (Figs. 27-40)
An opening or hole in bone located on the external
surface of the mandible in the region of the
mandibular premolars
Appearance
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A small ovoid or round radiolucent area located in
the apical region of the mandibular premolars
Frequently misdiagnosed as a periapical lesion
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Mylohyoid Ridge
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Description
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Iannucci & Howerton (pp. 337-338) (Fig. 27-41)
A linear prominence of bone located on the
internal surface of the mandible
Appearance
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A dense radiopaque band that extends downward
and forward from the molar region
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41
Mandibular Canal
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Description
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Iannucci & Howerton (p. 338) (Fig. 27-42)
A tubelike passageway through bone that travels
the length of the mandible
Houses the inferior alveolar nerve and blood
vessels
Appearance
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A radiolucent band outlined by two thin
radiopaque lines that represent the cortical walls
of the canal
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42
Internal Oblique Ridge
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Description
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Iannucci & Howerton (pp. 338-339) (Figs. 27-43)
A linear prominence of bone located on the
internal surface of the mandible the ramus
Appearance
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A radiopaque band that extends downward and
forward from the ramus
 When both appear, the external oblique ridge is
superior to the internal oblique ridge.
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43
External Oblique Ridge
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Description
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Iannucci & Howerton (p. 339) (Figs. 27-44, 27-45)
A linear prominence of bone located on the
external surface of the body of the mandible
Appearance
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A radiopaque band extending downward and
forward from the anterior border of the ramus of
the mandible
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Submandibular Fossa
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Description
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Iannucci & Howerton (p. 339) (Fig. 27-46)
A scooped-out, depressed area of bone located
on the internal surface of the mandible inferior to
the mylohyoid ridge
Appearance
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A radiolucent area in the molar region below the
mylohyoid ridge
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Coronoid Process
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Description
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Iannucci & Howerton (pp. 339-340) (Fig. 27-47)
A marked prominence of bone on the anterior
ramus of the mandible
Radiographic appearance
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A triangular radiopacity superimposed over, or
inferior to, the maxillary tuberosity region
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46
Normal Tooth Anatomy
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Tooth structure
Supporting structures
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Tooth Structure
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Iannucci & Howerton (p. 340) (Figs. 27-48, 27-49,
27-50)
Enamel – the outermost radiopaque layer of
the crown of a tooth
Dentin – comprises most of the tooth
structure, not as radiopaque as enamel
Dentinoenamel junction – the junction
between dentin and enamel
Pulp Cavity – a pulp chamber and pulp
canals
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Supporting Structures
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Iannucci & Howerton (pp. 340-341) (Figs. 27-51)
Anatomy of alveolar bone
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Lamina dura
 Alveolar crest
 Periodontal ligament space
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Shape and density of alveolar bone
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Anterior regions
Posterior regions
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Anatomy of Alveolar Bone
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Iannucci & Howerton (pp. 341) (Fig. 27-52)
Anatomic landmarks of the alveolar process
include the lamina dura, alveolar crest, and
periodontal ligament space.
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Lamina Dura
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Iannucci & Howerton (p. 341) (Fig. 27-53)
Description
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The wall of the tooth socket
 Made of dense cortical bone
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Appearance
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A dense radiopaque line that surrounds the root of
a tooth
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Alveolar Crest
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Description
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Iannucci & Howerton (pp. 341-342) (Fig. 27-54)
The most coronal portion of the alveolar bone
found between teeth
Appearance
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Appears radiopaque, typically 1.5 to 2.0 mm.
below the cementoenamel junction
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52
Periodontal Ligament Space
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Description
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Iannucci & Howerton (pp. 341-342) (Fig. 27-55)
The space between the root of the tooth and the
lamina dura
Appearance
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A thin radiolucent line around the root of a tooth
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Shape and Density of Alveolar Bone
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Iannucci & Howerton (pp. 341-342) (Fig. 27-56)
Anterior regions
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Normal alveolar crest appears pointed and sharp
between the teeth.
The alveolar crest appears as a dense radiopaque
line in the anterior region.
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Shape and Density of Alveolar Bone
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Iannucci & Howerton (p. 342) (Fig. 27-57)
Posterior regions
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Normal alveolar crest appears flat and smooth
between the teeth.
The alveolar crest appears less dense and less
radiopaque than the alveolar crest seen in the
anterior region.
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