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The following slides identify anatomical structures seen on intraoral radiographs.

Intraoral Anatomy

Maxillary Incisor

Nasal septum

Inferior concha

Nasal fossa

Nasal spine

Incisive foramen

Nose

Median palatine suture

e

f

a = nasal septumb = inferior conchac = nasal fossad = anterior nasal spine

e = incisive foramenf = median palatal suture

b

ad

c

facial view palatal view

Nasal septum

facial view

a

Inferior concha

facial view

Nasal fossa

facial view

Anterior nasal spine

facial view

Incisive foramen

palatal view

Median palatal suture

palatal view

Soft tissue of the nose

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.

The red arrows point to the soft tissue of the nose. The green arrows identify the lip line.

Maxillary Canine

Floor of nasal fossa

Maxillary sinus

Lateral fossa

Nose

Floor of nasal fossa (red arrows) and anterior border of maxillary sinus (blue arrows), forming the inverted (upside down) Y. Y

facial view

Soft tissue of the nose

Red arrows point to nasolabial fold. Also note the inverted Y.

Zygomatic process

Sinus septumSinus recess

Maxillary sinus

Maxillary Premolar

a = malar processb = sinus recessc = sinus septumd = maxillary sinus

b

a c d

b

dca

facial view

Malar (zygomatic) process. U or j-shaped radiopacity, often superimposed over the roots of the molars, especially when using the bisecting-angle technique. The red arrows define the lower border of the zygomatic bone.

facial view

Sinus septum. This septum is composed of folds of cortical bone that arise from the floor and walls of the maxillary sinus, extending several millimeters into the sinus. In rare cases, the septum completely divides the sinus into separate compartments.

facial view

Sinus recess. Increased area of radiolucency caused by outpocketing (localized expansion) of sinus wall. If superimposed over roots, may mimic pathology.

facial view

Pneumatization. Expansion of sinus wall into surrounding bone, usually in areas where teeth have been lost prematurely. Increases with age.

Maxillary Molar

Maxillary sinusSinus recess

Zygoma

Pterygoid plate

Hamularprocess

Coronoid process Maxillary tuberosity

g

d

a

e

f

a = maxillary tuberosity* e = zygoma (dotted lines)b = coronoid process f = maxillary sinusc = hamular process g = sinus recessd = pterygoid plates

* image of impacted third molar superimposed

c

b

facial view

d

b

a

e

c f

g

Hamular process (white arrows) and pterygoid plates (purple arrows). The hamular process is an extension of the medial pterygoid plate of the sphenoid bone, positioned just posterior to the maxillary tuberosity.

facial view

Mandibular Incisor

Mental ridge

Genial tubercles Lingual foramen

Mental fossa

b = genial tubercles

a = lingual foramen c = mental ridge

d = mental fossa

ab

cd

facial viewlingual view

Lingual foramen. Radiolucent “hole” in center of genial tubercles. Lingual nutrient vessels pass through this foramen.

lingual view

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

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

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 in older persons with thin bone, and in those with high blood pressure or advanced periodontitis.

Mandibular Premolar

Mylohyoid ridge

Mandibular canal

Mental foramen

Submandibular gland fossa

c

b = mandibular canald = mental foramen

a = mylohyoid ridge (internal oblique)c = submandibular gland fossa

facial view lingual view

c

add b

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

facial view

Mandibular canal. (Inferior alveolar canal). Runs downward from the mandibular foramen to the mental foramen, passing close to the roots of the molars. More easily seen in the molar periapical.

lingual view

Submandibular gland fossa. The depression below the mylohyoid ridge where the submandibular gland is located. More obvious in the molar periapical film.

Mental foramen. Usually located midway between the upper and lower borders of the body of the mandible, in the area of the premolars. May mimic pathology if superimposed over the apex of one of the premolars.

facial view

Mandibular Molar

External oblique ridge

Submandibular gland fossa

Mandibular canal

Mylohyoid ridge(internal oblique)

facial view lingual view

b

c

ab

a = external oblique ridgec = mandibular canal

b = mylohyoid ridged = submandibular gland fossa

dd

ab

c

dd

a = external oblique ridgeb = mylohyoid ridgec = mandibular canald = submandibular gland fossa

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 a distinct 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).

facial view

Mylohyoid ridge (internal oblique). Located on the lingual surface of the mandible, extending from the third molar area to the premolar region. Serves as the attachment of the mylohyoid muscle.

lingual view

facial view

Mandibular (inferior alveolar) canal. Arises at the mandibular foramen on the lingual side of the ramus and passes 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.

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.

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 problem when 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.

Identify the anatomical structures on the following four slides.

Slide # 1

A. The red arrows identify the ?

Floor of the nasal fossa

Slide # 2

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 ?

Coronoid process

Maxillary sinus*

Sinus septum

Zygomatic process

*(pneumatized into maxillary tuberosity)

Slide # 3

A. The small radioluceny identified by the green arrow is the ?

Lingual foramen

Slide # 4

A. The radiopacity identified by the blue arrows is the ?

B. The orange arrow identifies the ?

Mylohyoid ridge

Submandibular gland fossa

Panoramic Radiography