 Hello everyone, welcome back to another session in dentistry and more, today we have extra aural radiography. So we have learned in detail about intraoral radiography, the faulty radiographs in intraoral radiography and the various techniques also we covered. Now let us move on to extra aural radiography. As the name suggests the extra aural radiography, the film will be placed outside the mouth. So it is indicated when fractures of the maxillofacial skeleton happen or the fractures of the skull or investigation of the intra or diseases affecting the skull base and vault also it is used for TMJ disorders. So this is extra aural cassette and the film, so this is the film and this is where we keep our film. So main maxillofacial skull projections are standard occipitamental that is 0 degree occipitamental and 30 degree occipitamental posterior anterior view that is PA skull sometimes referred to as occipitofrontal posterior anterior that is posterior anterior PA of jaws reverse thorn projection and rotated posterior anterior projection through lateral skull and submental vortex. These are the various projections of maxillofacial or skull structures. So this is how we keep our, this is X-ray, the entire part is X-ray machine here we will please our the extra aural radiograph and X-ray will be produced from here. So this session is about why each projection is taken and how it is taken and what the resultant radiograph should look like and which normal anatomic features it shows. So the first one is standard occipitamental or 0 degree occipitamental. This projection shows the facial skeleton and maxillary antra okay the facial skeletal and maxillary antra and avoids superimposition of the dense bonds of base of the skull. It is indicated when we need investigation of the maxillary antra or to detect the following middle third facial fractures such as for one, two and three or zygomatic complex, naso-ethmoidal complex, orbital blood fractures, coronoid process fractures or to investigate the frontal and ethmoidal sinuses or to investigate the suenoidal sinus. So in suenoidal sinus case projection needs to be taken with patient's mouth open. So the technique and positioning the patient is positioned facing image receptor with the head tip back so that the radiographic baseline is at 45 degree to the image receptor okay. So this is how we keep the patient the line is horizontal 0 degree to the occipit whereas the radiographic baseline this is a radiographic baseline this is at 45 degree 45 degree to the image receptor this is a image receptor or x-ray film. So the radiographic baseline this is the baseline it will be at 45 degree to the x-ray film and the x-ray beam is horizontal or at 0 degree okay. So the patient is positioned facing the image receptor with the head tip back so that the radiographic baseline is at 45 degree to the image receptor with the so-called nose chin position okay. So this is a nose chin position the nose chin position where the chin will be touching the x-ray film. This positioning drops the dense bone of base of the skull downwards and raises the facial bones so they can be seen. So the x-ray tube head is positioned with the central x-ray horizontal center through the occipit so the central x-ray is 0 degree to the occipit okay. So this is the radiograph so this is the radiograph shown here so where the major anatomical features are drawn in such as orbit anterior cranial fozor this is a anterior cranial fozor then posterior ethmoid sinus the coronoid process of zygomatic arch so pediosurface of peterous temporal bone and the lower border of mandible this is the lower border of mandible then the warmer bones. So this will be the maxillary anterom, infra-orbital, foramen, nasal septum, then frontal sinus all are well visible in this 0 degree projection that is our standard occipito mental projection okay. Now let's move on to the second technique that is 30 degree occipito mental this projection also shows a facial skeleton but from a different angle from the 0 degree occipito mental which enabling certain bony displacement to be detected so many indications to detect the middle third facial fractures such as leiford 1 2 and 3 and also cornoid process fractures. So the technique is a little bit different because here the angulation of x-ray beam is at 30 degree okay rest all positions are same as 0 degree occipito mental 0 degree occipito mental the x-ray beam was at 0 degree to occipito mental but this is at 30 degree okay this is a 30 degree. So the patient is in exactly the same position as for the 0 degree occipito mental the head tip back radiographic baseline is at 45 degree to the image receptor in the nose chin position but the x-ray tube head is aimed downwards from above the head with the central ray at 30 degree to the horizontal line okay centered through the lower border of the orbit so this is the lower border of orbit so it is going through the lower border of orbit so that is the difference between 0 degree occipito mental and 30 degree occipito mental. So this is almost like our early picture but it is more commonly giving a better view of frontal sinus and the cornoid process mastoid process trigomatic arch so all are well visible in 30 degree occipito mental now we have posterior view of the skull that is PA view the projection shows the skull vault primarily the frontal bones and the jaw it is mainly indicated for the fractures of the skull vault investigation of the frontal sinuses and the conditions affecting the cranium particularly pages this is of bone multiple myeloma hyper parathyroidism and intra cranial calcification in PA view the patient is positioned facing the image receptor with the head tipped forward so that the forehead and tip of the nose touch the image receptor the so-called forehead nose position so where the forehead and tip of the nose is stretching the x-ray film that is the forehead nose position the radiographic baseline is horizontal and at right angle to the image receptor just like our 0 degree occipito mental view and this positioning levels of the base of the skull and allows the vault of the skull to be seen without superimposition and the x-ray tube head is positioned with the central ray horizontally centered through the occipit so this occipit is almost 90 degree or it is parallel to the or it is similar to the 0 degree occipito mental view okay this is a posterior anterior so posterior anterior view clearly shows superior orbital fissure shadow of peterous temporal bone inferior surface of peterous temporal bone nasal septum all those features are clearly defined and also the sagittal suture now we have posterior anterior view of the jaw that is PA jaw or PA mandible this projection shows the posterior parts of the mandible it is not suitable for showing the facial skeleton because the super imposition of the base of the skull and nasal bone so it is indicated when fractures of the mandible involving posterior third of the body angle rame or low contella necks or if we have any suspected lesion such as cysts or tumors in the posterior third of the body or rame of the mandible or to not any medial lateral expansion or mandible or hypoplasia or hypoplasia or maxillofacial deformities and the technique is the patient is exactly the same position as for the posterior anterior skull view that is the head tipped forward the radiographic baseline horizontal and perpendicular to the image receptor in a forehead nose position and the x-ray tube head is again at horizontal that is 0 degree but now the central ray is centered through the cervical spine at the level of rame of mandible okay so this central rays moving through the rame of mandible okay so this is the rame of mandible it's almost the forehead nose position but the central ray is passing through the rame of mandible so now we'll get a picture like this x-ray that is nasal cavity nasal cavity mastoid process pitous temporal bone and the zygoma coronoid process contella neck all are well visible next we have reverse towns projection this is showing the contella heads and neck the original towns view that is an anterior posterior projection was designed to show the occipital region but also show the contils however since all skull views used in dentistry are taken conventionally in the posterior anterior direction the reverse towns is used that is a posterior anterior projection okay main indications high fractures of the contella necks intra capsular fractures of the tmj investigation of the quality of the articular surfaces of contella heads and tmj disorders contella hypoplasia or hypoplasia the technique and positioning this is like this okay the patient in forehead nose position with the mouth open and the x-ray beam is aimed upward at 30 degree this is at upward at 30 degree to horizontal okay so the patient is in the pa position that is head tip towards the forehead nose position but in addition the mouth is open that is the main feature of reverse town projection mouth is open and the radiographic baseline is horizontal and at right angle to the image receptor and opening the mouth takes the contella head out of the glenoid fossa so they can be seen the x-ray tube head is aimed upward from below the occiput with the central ray at 30 degree to the horizontal centered through the condyles okay so this is a position it gives a picture like this with posterior nasal fossa lateral terabyte plate maxillary incisors spinous process of cervical vertebra all are well visible now let's move on to rotated posterior anterior view so the indication when there is tons calcule in the parotid glands lesions and jasses or tumors in the ramus to not any medial lateral expansion or submacetric infection to not new bone formation so technique and positioning just like this the patient is positioned facing the image receptor with the occlusal plane horizontal and the tip of the nose touching the image receptor in the so-called normal head position this is a normal head position where just the tip of the nose is touching the x-ray film the head is then rotated 10 degree to the side of the interest this positioning rotates the bone of the back of the skull away from the side of the face under investigation but the x-ray tube head is positioned with the central ray horizontal aim down the side of the face so we can have a 10 degree change towards the area of interest so we get a x-ray like this where the mastoid air cells pittus temporal bone contella neck floor of the orbit zygomatic arch maxillary and from ankle of the mandibles are well visible now we have true lateral skull this projection shows the skull vault and facial skeleton from the lateral aspect the main difference between true lateral skull and the true syphilometric lateral skull taken on the syphilostat is that the true lateral skull is not standardized or reproducible this view is used when a single lateral view of the skull is required but not in authentic or growth studies it is indicated four fractures of the cranium and the cranial base middle third facial fractures to show possible downward and backward displacement of maxilla investigation of the frontal sphenoidal and maxillary sinuses and the conditions affecting skull walls particularly pages disease of bone multiple myeloma hyperparathyroidism and conditions affecting the cellar to Sika such as tumors of the pituitary gland in a chroma galley technique and positioning it is like this we keeping lateral side towards the image receptor that is a patient is positioned with the head turned through 90 degree so the side of the face touches the image receptor like this so the side of the face is touching the image receptor in this position the sagittal plane of the head is parallel to the image receptor so the sagittal plane is parallel to the image receptor and the x-ray tube head is positioned with the central ray that is at going at horizontal zero degree and perpendicular to the sagittal plane so it is going perpendicular to the sagittal plane okay and the image receptor centered through the external auditory meatus so the central ray is going through external auditory meatus so we get a picture like this so most of the structures are well visible in lateral cephalogram now we have sub-mental vertex view okay this projection shows a base of the skull sphenoid sinus and facial skeleton from below main indication for destructive or expansive lesions affecting the palate pterygoid region or base of skull investigation of the sphenoidal sinus assessment of thickness that is medial lateral thickness of the posterior part of the mandible before osteotomy or fractures of the zygomatic arches to show these thin bonds the sub-mental vertex is taken to with reduced exposure factors so it is like this the positioning of the face is very different that is the patient's head is tipped backwards and the x-ray beam is is aimed at 5 degree to the horizontal not zero degree at a 5 degree to the horizontal line okay so the patient is positioned facing away from the image receptor the head is tipped backward as far as possible so the vertex of the skull touches the image receptor so this is a vortex of the skull so in this position the radiographic baseline is vertical and parallel to the image receptor so this is the baseline which is parallel to the image receptor the x-ray tuber is aimed upward from below the chin with the central ray at 5 degree to the horizontal centered on an imaginary line joining the lower first molar so from this lower first molar line we keep at a 5 degree with corresponding to the lower first molar so it is aimed at 5 degree so we get a projection like this okay now we have jug handle view in jug handle view it is same as that in sub-mental vertex view but the thing is the exposure time exposure time is reduced approximately one third exposure time is reduced one third of sub-mental vertex view that is the difference between jug handle view and sub-mental vertex view that is a one third of the exposure time in sub-mental vertex view so this is a jug handle view next we have oblique lateral radiography it is just similar as true lateral radiography but only thing is there is a change in angulation okay so this is a true lateral radiography this is a oblique lateral radiography okay and it is mainly indicated for the assessment of presence or position of uninterrupted teeth detection of fracture of the mandible evaluation of lesions or conditions affecting the jaws including seas tumors giant solutions and other bone lesions or as an alternative with when intraoral views are unobtainable because of severe gagging or if the patient is unable to open the mouth or is unconscious has specific views of the salivary glands or temporal mandible joints indicated we can also think of this lateral view and this requires the cassette that is image receptor proper positioning of the x-ray tube and patient's head so this is the view through the radiographic keyhole so we can see a radiographic keyhole showing the right mandibular maxillary posterior teeth but the anterior teeth are obscured by the left ramus of the mandible okay so anterior teeth are obscured here and this is a view from underneath the left body of the mandible showing the right mandibular right mandible and right posterior mandibular teeth and right posterior mandibular teeth but the right maxillary teeth are obscured so this mandibular body obscuring the right mandibular sorry the right maxillary teeth so this is how it is done so this is the first one I was talking about standard occipito mental view it has got another name also which is known as waters view okay so this is I forgot to mention the waters view that is a standard occipito mental projection waters view this is commonly asked question waters view so that's all about extra oral radiography this is a commonly asked question the reverse turn projection a submento waters projection jug handle view waters view all are the commonly asked question so I'll come up with a new topic in dentistry and more thank you