radio graphic intraoral anatomy

8/9/2019 Radio Graphic Intraoral Anatomy

1/77

Intraoral Radiographic Anatomy

The following slides identify the anatomicalstructures that may be seen on intraoral films.

These structures are more likely to be seen when

using the bisecting angle technique because of the

increased vertical angulation (increased positive inthe maxilla and increased negative in the mandible)

commonly used with this technique. Since some of

the structures may be confused with pathology, it

is important to understand their normalappearance in order to make a proper diagnosis.

If you right click anywhere on the screen and select

Full Screen the slides will be easier to view.


2/77


3/77

e

f

a = nasal septum

b = inferior concha

c = nasal fossa

d = anterior nasal spine

e = incisive foramen

f = median palatal

suture

b

ad

c

facial view palatal view


4/77

Nasal septum

facial view


5/77

a

Inferior concha

facial view


6/77

Nasal fossa

facial view


7/77

Anterior nasal spine

facial view


8/77

Incisive foramen

palatal view


9/77

Median palatal suture

palatal view


10/77

Soft tissue of the nose


11/77

Red arrow points to

periapical lesion

(post-endo).

ab

e

a

db

Red arrows = lip line


12/77

g

Red arrow = mesiodens

(supernumerary tooth)

d

f

Blue arrow = chronicperiapical periodontitis.

Tooth # 9 is non-vital

(trauma) and needs endo.


13/77

Superior foramina of the nasopalatine canals (red

arrows). These foramina lie in the floor of the nasal

fossa. The nasopalatine canals travel downward to join

in the incisive foramen.


14/77

d

b a

The red arrows point to an

incisive canal cyst; the

orange arrow identifies

the root of tooth # 7.

All the incisors are non-vital

and have periapical lesions. The

purple arrows point to external

resorption; the blue arrow

identifies internal resorption.

f


15/77

The red arrows point to the soft tissue of the nose.

The green arrows identify the lip line.


16/77

0

Maxillary Canine

Floor of nasal fossa

Maxillary sinus

Lateral fossa

Nose


17/77

a = floor of nasal fossa

b = maxillary sinus

c = lateral fossa

(a & b form inverted Y)

a

c

b

a

c

b

facial view


18/77

Floor of nasal fossa (red arrows) and anterior

border of maxillary sinus (blue arrows), forming the

inverted (upside down) Y. Y

facial view


19/77

Lateral fossa. The radiolucency results from a

depression above and posterior to the lateral

incisor. To help rule out pathology, look for an

intact lamina dura surrounding the adjacent teeth.

facial view


20/77

Soft tissue of the nose

Red arrows point to nasolabial fold.

Also note the inverted Y.


21/77

The maxillary sinus

surrounds the root of the

canine, which may be

misinterpreted as

pathology.

The white arrows indicate the

floor of the nasal fossa. The

maxillary sinus (red arrows)

has pneumatized between the

2nd premolar and first molar


22/77

The red arrow identifies the lateral fossa. The pink

arrow points to CPP (chronic periapical periodontitis =

abscess, granuloma, etc.).


23/77

0

Zygomatic

process

Sinus septumSinus recess

Maxillary sinus

Maxillary Premolar


24/77

a = malar processb = sinus recess

c = sinus septum

d = maxillary sinus

b

a cd

b

dca

facial view


25/77

Malar (zygomatic) process. U or j-shaped

radiopacity, often superimposed over the rootsof the molars, especially when using the

bisecting-angle technique. The red arrows

define the lower border of the zygomatic bone.

facial view


26/77

Sinus septum. This septum is composed of folds

of cortical bone that arise from the floor and wallsof the maxillary sinus, extending several

millimeters into the sinus. In rare cases, the

septum completely divides the sinus into separate

compartments.

facial view


27/77

Sinus recess. Increased area of radiolucency

caused by outpocketing (localized expansion)of sinus wall. If superimposed over roots, may

mimic pathology.

facial view


28/77

Maxillary Sinus. An air-filled cavity lined with

mucous membrane. Communicates with nasal

cavity through 3-6 mm opening below middle

concha. Red arrows point to neurovascular

canal containing superior alveolar vessels and

nerves.

facial view


29/77

Blue arrows identify

radiopacity which is a

mucous retention cyst.

Note relatively recent

premolar extraction sites.

Green arrow points to

neurovascular canal.

The red arrows point to

the nasolabial fold. The

thicker cheek tissue

makes the area more

radiopaque posterior to

the line.


30/77

Pneumatization. Expansion of sinus wall into

surrounding bone, usually in areas where

teeth have been lost prematurely. Increaseswith age.


31/77

0Maxillary Molar

Maxillary sinus

Sinus recessZygoma

Pterygoid plate

Hamular

process

Coronoid process Maxillary tuberosity


32/77

g

d

a

e

f

a = maxillary tuberosity* e = zygoma (dotted lines)

b = coronoid process f = maxillary sinus

c = hamular process g = sinus recess

d = pterygoid plates

* image of impacted third molar superimposed

c

b

facial view

d

b

a

e

c f

g


33/77

Maxillary Tuberosity. The rounded elevationlocated at the posterior aspect of both sides of

the maxilla. Aids in the retention of dentures.

facial view

facial view


34/77

Coronoid process. A mandibular structure

sometimes seen on the maxillary molar periapicalfilm when using the bisecting angle technique

with finger retention (The mouth is opened wide,

moving the coronoid down and forward). Note the

supernumerary molar.

facial view


35/77

Hamular process (white arrows) and pterygoid plates

(purple arrows). The hamular process is anextension of the medial pterygoid plate of the

sphenoid bone, positioned just posterior to the

maxillary tuberosity.

facial view


36/77

Zygomatic (malar) bone/process/arch. The

zygomatic bone (white/black arrows) startsin the anterior aspect with the zygomatic

process (blue arrow), which has a U-shape.

The zygomatic bone extends posteriorly

into the zygomatic arch (green arrow).

facial view

facial view


37/77

Maxillary sinus. As seen in the above film, the floor of the

maxillary sinus flows around the roots of the maxillary molars

and premolars. The walls of the sinus may become very thin.

As a result, sinusitis may put pressure on the superior alveolarnerves resulting in apparent tooth pain, even though the tooth

is perfectly healthy. Note coronoid process (green arrow),

zygomatic bone (blue arrow), sinus septum (yellow arrow) and

neurovascular canal (orange arrows).

facial view


38/77

The maxillary sinus is evident

anterior to the second molar

(black arrows) but it

disappears posteriorly due to

the superimposition of the

zygomatic bone. The orange

arrows identify a mucous

retention cyst (retention

pseudocyst) within the sinus.

This film shows the coronoid

process (green arrow) and a

distomolar (blue arrow) that

has erupted ahead of the

third molar (red arrow). Adistomolar is a

supernumerary tooth that

erupts distal (posterior) to

the other molars.


39/77

The zygomatic process (green arrows) is a prominent U-

shaped radiopacity. Normally the zygomatic bone

posterior to this is very dense and radiopaque. In thispatient, however, the maxillary sinus has expanded into

the zygomatic bone and makes the area more

radiolucent (red arrows). The coronoid process (orange

arrow), the pterygoid plates (blue arrows) and the

maxillary tuberosity (pink arrows) are also identified.


40/77

This film shows the expansion of the borders of the

maxillary sinus through pneumatization (red arrows). This

expansion increases with age and it may be accelerated as

a result of chronic sinus infections. It is most commonly

seen when the first molar is extracted prematurely, as inthe film at right (the second and third molars have

migrated anteriorly to close the space). The coronoid

process is seen in the lower left-hand corner of each film.

The green arrow identifies a sinus recess. Note the two

distomolars in film at right (blue arrows).

M dib l I i


41/77

Mandibular Incisor

Mental ridge

Genial tubercles Lingual foramen

Mental fossa

facial viewlingual view


42/77

b = genial tubercles

a = lingual foramen c = mental ridge

d = mental fossa

a

b

cd

facial viewlingual view

lingual view


43/77

Lingual foramen. Radiolucent hole in center of

genial tubercles. Lingual nutrient vessels pass

through this foramen.

lingual view

lingual view


44/77

Genial tubercles. Radiopaque area in the midline,

midway between the inferior border of the mandible and

the apices of the incisors. Serve as attachments for the

genioglossus and geniohyoid muscles. May have

radiolucent hole in center (lingual foramen), but not on

this film. Note double rooted canine (red arrows).

lingual view

facial view


45/77

Mental ridge. These represent the raised portions of the

mental protuberance on either side of the midline. More

commonly seen when using the bisecting angle

technique, when the x-ray beam is directed at an

upward angle through the ridges.

facial view

facial view


46/77

Mental fossa. This represents a depression on the

labial aspect of the mandible overlying the roots of

the incisors. The resulting radiolucency may be

mistaken for pathology.

facial view


47/77

The radiolucent area above

corresponds to the location

of the mental fossa. However,this slide represents chronic

periapical periodontitis; these

teeth are non-vital, due to

trauma.

The orange arrows above

identify nutrient canals.

They are most often seen inolder persons with thin

bone, and in those with high

blood pressure or advanced

periodontitis.

0Mandibular Canine


48/77

0Mandibular Canine

Mental ridge

Genial tubercles

Lingual foramen

Mental foramen

Cortical bone

facial view lingual view


49/77

b2

a = mental ridge

c = mental foramen b2 = lingual foramen

b1 = genial tubercles

dc

da

db1

db2

facial view


50/77

Mental ridge. The raised portions of the mental

protuberance, sloping downward and backward

from the midline.

lingual view


51/77

Lingual foramen/genial tubercles. (See

description under mandibular incisor

above).

lingual view

facial view


52/77

The red arrows identify the mandibular canal

and the blue arrow points to the mental

foramen.

facial view

M dib l P l


53/77

Mandibular Premolar

Mylohyoid ridge

Mandibular canal

Mental foramen

Submandibulargland fossa



54/77

c

b = mandibular canal

d = mental foramen

a = mylohyoid ridge

(internal oblique)c = submandibular gland

fossa


c

add b

lingual view


55/77

Mylohyoid (internal oblique) ridge. This radiopaque

ridge is the attachment for the mylohyoid muscle.The ridge runs downward and forward from the

third molar region to the area of the premolars.

lingual view


56/77

facial view

Mandibular canal. (Inferior alveolar canal). Runs

downward from the mandibular foramen to themental foramen, passing close to the roots of the

molars. More easily seen in the molar periapical.


57/77

lingual view

Submandibular gland fossa. The depression below

the mylohyoid ridge where the submandibular glandis located. More obvious in the molar periapical film.


58/77


59/77

The mental foramen (blue

arrow) is adjacent to a

periapical lesion associated

with tooth # 21 (red arrow).

There is slight externalresorption on # 21.

The green arrow points to the

mental foramen. The yellow

arrow identifies a periapical

lesion on # 30. Note the

overextension of the silver pointin the distal root, the perforation

of the mesial root and the

amalgam protruding through

the perforation from the pulp

chamber.

M dib l M l


60/77

Mandibular Molar

External oblique

ridge

Submandibular

gland fossa

Mandibular canal

Mylohyoid ridge

(internal oblique)



61/77


b

c

ab

a = external oblique ridge

c = mandibular canal

b = mylohyoid ridge

d = submandibular gland

fossa

dd


62/77

ab

cdd

a = external oblique ridgeb = mylohyoid ridge

c = mandibular canal

d = submandibular gland fossa

facial view


63/77

External oblique ridge. A continuation of the anterior

border of the ramus, passing downward and forward

on the buccal side of the mandible. It appears as adistinct radiopaque line which usually ends

anteriorly in the area of the first molar. Serves as an

attachment of the buccinator muscle. (The red

arrows point to the mylohyoid ridge).

lingual view


64/77

Mylohyoid ridge (internal oblique). Located on the

lingual surface of the mandible, extending from thethird molar area to the premolar region. Serves as

the attachment of the mylohyoid muscle.

lingual view

f i l i


65/77

facial view

Mandibular (inferior alveolar) canal. Arises at the

mandibular foramen on the lingual side of the ramus andpasses downward and forward, moving from the lingual

side of the mandible in the third molar region to the

buccal side of the mandible in the premolar region.

Contains the inferior alveolar nerve and vessels.

lingual view


66/77

Submandibular gland fossa. A depression on the

lingual side of the mandible below the mylohyoid

ridge. The submandibular gland is located in this

region. Due to the thinness of bone, the trabecularpattern of the bone is very sparse and results in the

area being very radiolucent. The fact that it occurs

bilaterally helps to differentiate it from pathology.


67/77

The external oblique ridge (red arrows) and the

mylohyoid ridge (blue arrows) usually run parallel

with each other, with the external oblique ridge

always being higher on the film.


68/77

The mandibular canal (red arrows identify inferior border

of canal) usually runs very close to the roots of the

molars, especially the third molar. This can be a problemwhen extracting these teeth. Note the extreme dilaceration

(curving) of the roots of the third molar (green arrow) in

the film at left. The film at right shows kissing

impactions located at the superior border of the canal.


69/77

Identify the anatomical structures

on the following eight slides.

Enter answers on the

accompanying answer sheet.

Slide # 1


70/77

A. The red arrows identify the ?

Slide # 2


71/77

A. The red arrow points to the ?

B. The white arrows identify the ?

C. The blue arrow points to the ?

D. The yellow arrow identifies the ?

Slide # 3


72/77

A. The small radioluceny identified by

the green arrow is the ?

Slide # 4


73/77

A. The radiopacity identified by theblue arrows is the ?

B. The orange arrow identifies the ?

Slide # 5


74/77

A. The yellow arrows point to the ?

B. The red arrows identify the ?

Slide # 6


75/77

A. The red arrow points to the ?

B. The orange arrow points to the ?

C. The blue arrows point to theradiolucent line known as the ?

Slide # 7


76/77

A. The red arrows point to the ?

Slide # 8


77/77

A. The red arrows identify the ?

B. What is the name of the radiolucent

area surrounding the canal?

radio graphic intraoral anatomy

Documents