ACJ Normal Anatomy Landmarks 01

V-shape opaque projection on periapical radiographs of the maxillary central incisors, located in the middle ( 1.5 to 2 cm above the alvelora crest ).
Usually at or just below the junction of the inferior end of the nasal septum and the inferior outline of the nasal aperture.

Nasal Aperture:
On Periapical radiographs of the incisors the inferior border of the fossa aperture as a radiopque line extending bilaterally away from the base of the anterior nasal spine.
Above this line is the radiolucent space of the inferior portion of the cavity.

Incisive Foramen ( Nasalpalatine or anterior palatine foramen )
-The oral terminus of the nasalpalatine canal.
- projected b/w roots and region of the middle and apical thirds of the central incisors.
-potential site for cyst formation.
- Presence of a cyst is predumed if the width of the foramen exceeds 1 cm.

Lateral Fossa (Incisive fossa)
- a gentle depression in the maxilla near the apex of the lateral incisor.
- On periapical of this region it may apper diffusely radiolucent.

Zygomatic process of maxilla
-An extension of latetal maxillary surface that arises in the region of the apices of the first and second molars and attached to the zygomatic bone.

Nose:
-The image of the nose has slightly opaque appearance with a sharp border seen on xrays of upper central and lateral incisors ( superimposed over the roots of these teeth)

Nasolabial Fold
An oblique line demarcating a region that appears to be covered by a veil of slight radiopacity frequently traverses periapical radiographs of the premolar region. The line of contrast is sharp, and the area of increased radiopacity is posterior to the line.

Maxillary tubersity
This is a bony prominence distal to last molar ik maxillaty arch. It apperas as a radiopaque dense structure.

Part of the sphenoid bone, located posterior to the maxilla.
• There are two: the medial and lateral pterygoid plates.
• The medial pterygoid plate ends with the pterygoid hamulus, a small, hook-like process.
• On panoramic or posterior maxillary periapical X-rays, they appear as thin vertical radiopaque projections behind the maxillary tuberosity.

Genial Tubercles (Mental Spine)
bony protuberances located on the lingual surface of the mandible slightly above the inferior border and in the midline.
serve to attach the genioglossus muscles (at the superior tubercles) and the geniohyoid muscles (at the inferior tubercles) to the mandible.
Usually well visualized on mandibular occlusal radiographs as one or more small projections.

Lingual Foramen:
a foramen on the lingual surface of the midline of the mandible in the region of the genial tubercles
typically visualized as a single round radiolucent canal with a well-defined opaque border lying in the midline below the level of the apices of the incisors.

Genial Tubercles (Mental Spine)
bony protuberances located on the lingual surface of the mandible slightly above the inferior border and in the midline.
serve to attach the genioglossus muscles (at the superior tubercles) and the geniohyoid muscles (at the inferior tubercles) to the mandible.
Usually well visualized on mandibular occlusal radiographs as one or more small projections.

Mental Ridge (protuberance)
On periapical radiographs of the mandibular central incisors, the mental ridge may occasionally be seen as two radiopaque lines sweeping bilaterally forward and upward toward the midline.

Mental fossa
a depression on the labial aspect of the mandible extending laterally from the midline and above the mental ridge.

Mental Ridge (protuberance)
On periapical radiographs of the mandibular central incisors, the mental ridge may occasionally be seen as two radiopaque lines sweeping bilaterally forward and upward toward the midline.

Mandibular tori (singular: torus mandibularis)
• Mandibular tori are benign bony outgrowths (exostoses) found on the lingual (tongue) surface of the mandible, most commonly in the premolar region and above the mylohyoid line.
• They’re made of dense cortical bone and sometimes a thin layer of trabecular bone inside.

Mental Foramen
the anterior limit of the inferior dental canal that is apparent on periapical radiographs.
seen about halfway between the lower border of the mandible and the crest of the alveolar process, usually in the region of the apex of the second premolar. (may be projected anywhere from just mesial of the permanent first molar roots to as far anterior as mesial of the first premolar root)
When the mental foramen is projected over one of the premolar apices, it may mimic periapical disease → pay attention to the normal lamina dura and PDL.

Mental Foramen
the anterior limit of the inferior dental canal that is apparent on periapical radiographs.
seen about halfway between the lower border of the mandible and the crest of the alveolar process, usually in the region of the apex of the second premolar. (may be projected anywhere from just mesial of the permanent first molar roots to as far anterior as mesial of the first premolar root)
When the mental foramen is projected over one of the premolar apices, it may mimic periapical disease → pay attention to the normal lamina dura and PDL.

Inferior Alveolar Canal
appears as a dark linear shadow with thin radiopaque superior and inferior borders cast by the lamella of bone that bounds the canal.

Inferior Alveolar Canal
appears as a dark linear shadow with thin radiopaque superior and inferior borders cast by the lamella of bone that bounds the canal

Submandibular Gland Fossa
a bone depression on the lingual surface of the mandibular body, immediately below the mylohyoid ridge in the molar area.
often appears as a radiolucent area with the sparse trabecular pattern

Nutrient Canals:
carry a neurovascular bundle and appear as radiolucent lines of uniform width.
most often seen on mandibular periapical radiographs running vertically from the inferior dental canal directly to the apex of a tooth or into the interdental space between the mandibular incisors.
may appear as a small round radiolucency if they are oriented perpendicular to the cortex.

External Oblique Ridge
a continuation of the anterior border of the mandibular ramus. It follows an anteroinferior course lateral to the alveolar process.

Coronoid Process
- frequently apparent on periapical radiographs of the maxillary molar region as a triangular radiopacity, with its apex directed superiorly and somewhat anteriorly, superimposed on the region of the third molar.

Coronoid Process
- frequently apparent on periapical radiographs of the maxillary molar region as a triangular radiopacity, with its apex directed superiorly and somewhat anteriorly, superimposed on the region of the third molar.

Maxillary Sinus
The borders of the maxillary sinus appear on periapical radiographs as a thin, delicate, tenuous radiopaque line.
In adults the sinuses usually extend from the distal aspect of the canine to the posterior wall of the maxilla above the tuberosity.
In older adults the sinus may extend farther into the alveolar process, and in the posterior region of the maxilla its floor may appear considerably below the level of the floor of the nasal cavity.
Anteriorly each sinus is restricted by the canine fossa and is usually seen to sweep superiorly, crossing the level of the floor of the nasal cavity in the premolar or canine region. Consequently, on periapical radiographs of

Maxillary Sinus
The borders of the maxillary sinus appear on periapical radiographs as a thin, delicate, tenuous radiopaque line.
In adults the sinuses usually extend from the distal aspect of the canine to the posterior wall of the maxilla above the tuberosity.
In older adults the sinus may extend farther into the alveolar process, and in the posterior region of the maxilla its floor may appear considerably below the level of the floor of the nasal cavity.
Anteriorly each sinus is restricted by the canine fossa and is usually seen to sweep superiorly, crossing the level of the floor of the nasal cavity in the premolar or canine region. Consequently, on periapical radiographs of

Lateral Fossa (Incisive fossa)
- a gentle depression in the maxilla near the apex of the lateral incisor.
- On periapical of this region it may apper diffusely radiolucent

Lateral Fossa (Incisive fossa)
- a gentle depression in the maxilla near the apex of the lateral incisor.
- On periapical of this region it may apper diffusely radiolucent.

• Intermaxillary Suture (median suture)

a thin radiolucent line in the midline on periapical radiographs between the two portions of the premaxilla.
extends from the alveolar crest between the central incisors superiorly through the anterior nasal spine and continues posteriorly between the maxillary palatine processes to the posterior aspect of the hard palate.

Nasolabial Fold
An oblique line demarcating a region that appears to be covered by a veil of slight radiopacity frequently traverses periapical radiographs of the premolar region. The line of contrast is sharp, and the area of increased radiopacity is posterior to the line.

Genial Tubercles (Mental Spine)
bony protuberances located on the lingual surface of the mandible slightly above the inferior border and in the midline.
serve to attach the genioglossus muscles (at the superior tubercles) and the geniohyoid muscles (at the inferior tubercles) to the mandible.
Usually well visualized on mandibular occlusal radiographs as one or more small projections.

The hamular process, also known as the pterygoid hamulus, is a hook-like projection of bone located on the medial pterygoid plate of the sphenoid bone.

Mental Foramen
the anterior limit of the inferior dental canal that is apparent on periapical radiographs.
seen about halfway between the lower border of the mandible and the crest of the alveolar process, usually in the region of the apex of the second premolar. (may be projected anywhere from just mesial of the permanent first molar roots to as far anterior as mesial of the first premolar root)
When the mental foramen is projected over one of the premolar apices, it may mimic periapical disease .

Alveolar bone
Normally the level of the alveolar bone is 1.5-2mm apical to the CEJ of the adjacent teeth.
In the anterior region the crest is sharp and pointed between the incisors.
Posteriorly it is flat, aligned parallel with and slightly below a line connecting the CEls of the adjacent teeth.

Periodontal ligament (PDL)
Radiographically seen as a radiolucent line on inside of lamina dura
PDL is thinner in the middle of the root and slightly wider near the alveolar crest and root apex (average width: 0.5 mm).
Position in relation to tooth can determine if lesion is attached to tooth structure (inside PDL) or not (outside
PDL).
Widening of the periodontal ligament space: Increased width of periodontal ligament space due to inflammation.
Etiology: pulp necrosis, root fracture, trauma from occlusion, malignancies, scleroderma (generalized PDL)

Incisive Foramen ( Nasalpalatine or anterior palatine foramen )
-The oral terminus of the nasalpalatine canal.
- projected b/w roots and region of the middle and apical thirds of the central incisors.
-potential site for cyst formation.
- Presence of a cyst is predumed if the width of the foramen exceeds 1 cm.

Intermaxillary Suture (median suture)

a thin radiolucent line in the midline on periapical radiographs between the two portions of the premaxilla.
extends from the alveolar crest between the central incisors superiorly through the anterior nasal spine and continues posteriorly between the maxillary palatine processes to the posterior aspect of the hard palate.

Lateral Fossa (Incisive fossa)
- a gentle depression in the maxilla near the apex of the lateral incisor.
- On periapical of this region it may apper diffusely radiolucent.

Nose:
-The image of the nose has slightly opaque appearance with a sharp border seen on xrays of upper central and lateral incisors ( superimposed over the roots of these teeth)

The nasal septum is the wall of bone and cartilage that divides the nasal cavity into two passages, separating the left and right nostrils. It's a crucial structure for maintaining the shape of the nose and ensuring proper airflow

V- shape opaque projection on periapical radiographs of the maxillary central incisors, located in the middle ( 1.5 to 2 cm above the alvelora crest ).
Usually at or just below the junction of the inferior end of the nasal septum and the inferior outline of the nasal aperture.