Panoramic films (OPTs/DPTs/OPGs) are a form of extra-oral radiograph that we take in dentistry. They provide an overview of the patient’s dentition as well as surrounding anatomy. You can see more about why we do panoramic films here.
Interpreting OPTs can be quite difficult if you’ve not seen many before and the aim of this post is to make you familiar with some of the key anatomical landmarks on this radiograph.
Anatomy of the Mandible
The mandibular condyle (brown highlight) will be seen as a rounded, radiopaque area located within the glenoid fossa towards the lateral aspects of the panoramic film.
The coronoid process (yellow highlight) is found medial to the condyle as a radiopaque, triangular area. It may superimpose over the maxillary tuberosity and the maxillary sinus.
The glenoid fossa (red line) is the concave area in the zygomatic process of the temporal bone – it is a key component of the temporomandibular joint (TMJ). Medial to the glenoid fossa, we can see the articular eminence (purple highlight).
If we then follow on down from the condyle and coronoid processes, we reach the ramus of the mandible (blue highlight). This then leads on to the body of the mandible (green highlight). The location these join at is the angle of the mandible (purple line).
Within the ramus of the mandible and going through the body of the mandible, you will notice a radiolucent band which is surrounded by two radiopaque bands – this is the inferior alveolar nerve canal (red lines) where the inferior alveolar nerve travels through. This will then travel to a radiolucent round/ovoid area around the apices of the lower first and second premolars – this is the mental foramen (blue highlight). The mental nerve exists from here.
The lower border of the mandible (orange highlight) is seen as a thick, radiopaque band.
Anatomy of the Maxilla
The maxillary sinuses (blue highlight) are seen as large, radiolucent areas above the maxillary dentition.
We can also identify the walls of the maxillary sinus. Panoramic films are carried out by rotation of the machine around the patient’s head – as a result, we should think of the image as the patient’s face flattened out. Therefore, on an OPT, we can see the posterior walls of the sinus (pink line) and the floor of the sinus (green line). These are seen as thin, radiopaque lines surrounding the maxillary sinus radiolucency. These lines are often close to the roots of the maxillary teeth.
The zygomatic process of the maxilla (red line) can also be seen as a radiopaque U/J/V-shaped line around the upper first/second molar teeth.
Anatomy of the Nose
We can see the borders of the nasal cavity medial to the walls of the maxillary sinus. The nasal cavity itself is highlighted blue.
The nasal septum (blue highlight) is seen as a radiopacity at the centre of the nasal cavity. Inferior nasal turbinates (pink highlight) are usually visible as round
The floor of the nasal cavity/hard palate (green highlight) is seen as a thin, radiopaque line. This may be superimposed over the maxillary sinus or maxillary teeth.
Anatomy of the Midface
The orbital rim (red line) can often be seen as a thick, semi-circular, radiopaque line superior to the maxillary sinuses.
Lateral to the maxillary sinuses, we can see the pterygomaxillary fissure (green highlight). This is an inverse teardrop radiolucency, surrounding by a thin radiopaque line.
The zygomatic bone (purple highlight) can also be identified as a radiopacity if we follow laterally from from the zygomatic process of maxillary bone. It will usually be superimposed over the maxillary tuberosity and pterygomaxillary fissure.
The external auditory meatus (red highlight) is seen as a round/ovoid radiolucent area lateral to the mandibular condyle and glenoid fossa.
The soft tissue of the earlobe (blue line) can also be seen as a radiopaque area roughly around the ramus of the mandible.
The cervical spine (purple highlight) is typically superimposed over the centre of the OPT – this often makes interpretation of anterior anatomy difficult. Depending on patient positioning, the cervical spine may also be present laterally on the film.
Adjacent to the cervical spine, if it is present laterally, you can see radiopaque pointed structures which are the styloid processes (yellow highlight).
Inferior to, or along, the lower border of the mandible, we would see the hyoid bone (green highlight) as a radiopaque structure either side.
The soft palate (red highlight) is a radiopaque mass seen next to the hard palate but with lower density due to the lack of bone.
There are also several other airspaces that can be identified on panoramic films. The nasopharynx (red highlight) is a radiolucent area coming from the nasal cavity. Below this, we have the oropharynx (purple highlight) which is a radiolucent area jointed to the oral cavity. Finally, below this, we have the hypopharynx (pink highlight).
Useful Links & Recommended Reading
- Essentials of Dental Radiography and Radiology
- Dr G’s Toothpix
- Single Best Answer Questions for Dentistry
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