Normal Anatomy

Orbit

A bony cavity that contains the eyeball. Appears as a round radiolucent compartment with radiopaque borders superior to the maxillary sinuses. Many times, only the inferior border of this is visible.

Glenoid Fossa

A concave, depressed area of the temporal bone. The mandibular condyle rests here. It is located anterior to the mastoid process and the external auditory meatus. Appears as a concave radiopacity superior to the mandibular condyle. Not see on PA

Infraorbital Foramen

A hole or opening in bone inferior to the border of the orbit. Appears radiolucent. May be superimposed over the sinus. Not seen on PA

External Auditory Meatus

A hole or opening in the temporal bone located superior and anterior to the mastoid process. Appears as a round or oval radiolucency. Not seen on PA

Internal Oblique Ridge

A linear prominence of bone located in the internal surface of the mandible that extends downward and forward from the ramus.

Mylohyoid Ridge

A linear prominence of bone located in the internal surface of the mandible that extends from the molar region downward and forward toward the lower border of the mandibular symphysis.

External Oblique Ridge

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

Mental Ridge

A linear prominence of cortical bone on the external surface of the anterior portion of the mandible that extends from the premolar area to the midline. Appears radiopaque.

Inferior Border of Mandible

A linear prominence of cortical bone that defines the lower border of the mandible. Appears as a fence radiopaque band outlining the border of the mandible

Styloid Process

A long pointed and sharp projection of bone that extends downward from the inferior surface of the temporal bone. It is located anterior to the mastoid process. Appears as a long radiopaque spine. Not seen on PA

Coronoid Process

A marked prominence of bone found in the anterior superior ramus. Appears as a triangular radiopacity posterior to the maxillary tuberosity region.

Mastoid Process

A marked prominence of bone located posterior and inferior to the TMJ. It is part of the temporal bone. On a pano, it appears as a rounded radiopacity located posterior and inferior to the TMJ area. Not seen on a PA

Tongue

A movable muscular organ attached to the floor of the mouth. Appears as a radiopaque area superimposed over maxillary posterior teeth

Pterygomaxillary Fissure

A narrow space or cleft that separates the lateral Pterygoid plate and the maxilla. Appears as a radiolucency. The zygoma is often superimposed on this. Not seen on PA

Incisive Canal

A passageway through bone that extends from the superior foramina of the incisive canal to the incisive foramen. Appears as a tubelike radiolucent area with radiopaque borders.

Nasal Cavity

A pear shaped compartment of bone located superior to the maxilla. Appears as a large radiolucent area.

Mandibular Foramen

A round of ovoid hole in bone on the lingual aspect of the ramus. Appears as a round radiolucency writhing the ramus of the mandible.

Mandibular Condyle

A rounded projection of bone extending from the posterior superior border of the ramus. Articulates with the glenoid fossa of the temporal bone.

Articular Eminence

A rounded projection of the temporal bone located anterior to the glenoid fossa. Appears as a rounded radiopaque projection of the bone anterior to the glenoid fossa. Not seen on PA

Coronoid Notch

A scooped out concavity of bone located distal to the coronoid process of the mandible.

Mental Fossa

A scooped out depressed area of bone located on the external surface of the anterior mandible above the mental ridge I the mandibular incisor region. Appears radiolucent

Anterior Nasal Spine

A sharp bony projection of the maxillary located at the anterior-inferior portion of the nasal cavity. Appears as a V-Shaped radiopaque area located at the intersection of the floor of the nasal cavity and the nasal septum

Hamulus

A small, hook like projection of bone that extends from the medial Pterygoid plate of the sphenoid bone. Located posterior to the maxillary tuberosity.

Lingula

A small, tongue-shaped projection of bone seen adjacent to the mandibular foramen. Appears as an indistinct radiopacity anterior to mandibular foramen.

Lingual Foramen

A tiny opening or hole in bone located on the internal surface of the mandible near the midline. Appears as a small radiolucent dot.

Mandibular Canal

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

Nasal Septum

A vertical bony wall that divides the nasal cavity into the right and left nasal fossae. Appears radiopaque.

Lateral Pterygoid Plate

A wing shaped bony projection of the sphenoid bone located distal to the maxillary tuberosity region. Appears as a radiopacity. Not seen on PA

Mental Foramen

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

Incisive Foramen

An opening or hole in bone that is located at the midline of the anterior portion of the hard palate. Appears as a small radiolucency between central incisors.

Ear

Appears as a radiopaque shadow that projects anteriorly and inferiorly from the mastoid process. Seen superimposed over the stylus process

Zygomatic Process of Maxilla

Bony projection of the maxilla that articulates with the zygoma or malar bone (cheek bone). Appears as a J or U shaped radiopacity superior to the maxillary first molar region.

Soft Palate and Uvula

Form a muscular curtain that separates the oral cavity from the nasal cavity. Appears as a diagonal radiopacity projecting posteriorly and inferiorly from the maxillary tuberosity region

Lipline

Formed by the positioning of the patients lips.

Maxillary Sinus and Floor of Maxillary Sinus

Paired cavities or compartments of bone that are located within the maxilla, superior to maxillary posterior teeth.

Angle of the Mandible

The area of the mandible where the body meets the ramus

Hard Palate

The bony wall that separates the nasal cavity from the oral cavity. Appears as a horizontal radiopaque band superior to the apices of maxillary teeth.

Zygoma

The cheekbone. It articulates with the zygomatic process of the maxilla. Appears as a radiopaque band that extends posteriorly from the zygomatic process of the maxilla.

Nasopharyngeal Air Space

The portion of the pharynx that is located posterior to the nasal cavity. Appears as a diagonal radiolucency located superior to the radiopaque shadow of the soft palate and the uvula

Glossopharyngeal Air Space

The portion of the pharynx that is posterior to the tongue. Appears as a vertical radiolucent band superimposed over the ramus.

Palatoglossal Air Space

The space between the plate and tongue. Appears as a horizontal radiolucent band located superior to the apices of maxillary teeth

Genial Tubercles

Tiny bumps of bone located in the lingual aspect of the mandible. Appear as a ring shaped radiopacity surrounding the lingual foramen

Maxillary Tuberosity

Rounded prominence of bone that extends posterior to the third molar region. Appears as a radiopaque bulge distal to the third molars.