Taking TMJ Temporomandibular joints axial projection if patient has possible fracture do not attempt to open mouth. Fractures and abnormal relationship/ range of motion between condyle and temporomadibular fossa. Image receptor used 18 x 24 cm or 8 x 10 inches, put in crosswise. Moving or stationary grid. 70 to 80 kV range, mAs 16, and Small focal spot.
AP AXIAL TMJ (Closed Mouth Position) |
AP Axial Projection (Closed Mouth) |
Contrast and density are sufficient to visualize condyloid process and temporomadibular fossa.
Sharp bony margins indicate no motion.
The Towne view is an angled anteroposterior radiograph of the skull and visualizes the petrous part of the pyramids, the dorsum sellae and the posterior clinoid processes, which are visible in the shadow of the foramen magnum.
This projection is used to evaluate for medial and lateral displacements of skull fractures, in addition to neoplastic changes and Paget disease.
- nuchal ridge is placed against the image detector
- the infraorbitomeatal line perpendicular to the image receptor
- anteroposterior axial projection
-
centering point
- the beam travels 30° caudad to the orbitomeatal line
-
collimation
- superior to include skin margins
- inferior to include base of skull
- lateral to the skin margins
- orientation
- detector size
- exposure
- SID
- grid
- dorsum sella overlies the foramen magnum
- petrous ridges are symmetrical
- if the dorsum sella projects above the foramen magnum it requires an increase in angle
- if the anterior arch of C1 is laying in the foramen magnum, less angle is required
- occipital bone and posterior fossa space better evaluated than with a non angulated AP view, which would have more skull base and facial bone overlap
- better than a conventional AP view for evaluating an occipital plagiocephaly involving the lambdoid suture
- may be a useful additional view for evaluating skull fractures 1
- 1. Shaffer MA, Doris PE. Increasing the diagnostic yield of portable skull films. Ann Emerg Med. 1982;11 (6): 303-6. Pubmed citation
The axiolateral temporomandibular joint (TMJ) view allows for visualization of the articular tubercle, mandibular condyle and fossa of the temporomandibular joint (TMJ).
This projection is useful in identifying structural changes and displaced fractures, assessing excursion and joint spaces in the trauma setting, and evaluating the presence of joint noises, trismus and occlusal alterations 1.
- the patient is seated upright with the side of interest closest to the detector.
- the head is placed in a true lateral position
- oblique the body to assist in patient positioning and reduce the object to image receptor distance
- depending on the projection (open or closed mouth) instruct the patient to open their mouth side and keep it there or keep it shut
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- left and right lateral and open and closed mouth
-
centering point
- central ray 25-30º caudad, centered 5 cm superior and 1 cm anterior to the external auditory meatus
-
collimation
- no more than 10 x 10 cm with temporomandibular joint of interest in the middle of the image
- orientation
- detector size
- exposure
- SID
- grid
- the temporomandibular joint closest to the image receptor should be clearly demonstrated without the superimposition of the opposite temporomandibular joint.
- the joint is central on the radiograph
- a radiolucent support such as a sponge can be used to help maintain the head position
- in patients that cannot stand unsupported, this projection can be performed prone to increase patient stability
- 1. Ferreira LA, Grossmann E, Januzzi E, Paula MVQd, Carvalho ACP. Diagnosis of temporomandibular joint disorders: indication of imaging exams. Brazilian Journal of Otorhinolaryngology. 2016;82:341-52.