Anatomical Landmarks in Oral & Maxillofacial Radiology PDF

12/15/2023 Anatomical landmarks Dr. Noha El-kersh Lecturer of Oral & Maxillofacial Radiology 1 2 1 12/15/2023 Teeth Supporting structure Maxilla Mandible Teeth Maxilla Supporting structures Mandible 3 TEETH ⦿ Enamel, dentin, cementum, ⦿Pulp, root canal ⦿Enamelodentin junction ⦿C-E junc...

12/15/2023 Anatomical landmarks Dr. Noha El-kersh Lecturer of Oral & Maxillofacial Radiology 1 2 1 12/15/2023 Teeth Supporting structure Maxilla Mandible Teeth Maxilla Supporting structures Mandible 3 TEETH ⦿ Enamel, dentin, cementum, ⦿Pulp, root canal ⦿Enamelodentin junction ⦿C-E junction ⦿Normal and developing 4 2 12/15/2023 Enamel The densest,RO,end in a fine edge at the CEJ ⦿ Dentin Major part of the tooth, diff. to see the DEJ in poor contrast radiograph ⦿ Cementum Density as dentine ,v. thin so difficult to be seen ⦿ Pulp chamber RL space,in the center, pulp horns(finger like projections) ⦿ 5 SUPPORTING STRUCTURE ⦿ Periodontal ligament space ⦿ Lamina dura ⦿ Alveolar crest ⦿ Cancellous bone 6 3 12/15/2023 SUPPORTING STRUCTURE Periodontal ligament space ⦿ R-L (radiolucent) space between root & lamina dura because it is composed primarily of collagen ⦿ Width of PDL (0.5mm) varied by individual teeth 7 SUPPORTING STRUCTURE Lamina dura It’s the bony wall of the tooth socket, Cortical bone that surrounds the PDL ⦿ Thin R-O (radiopaque) shadow bounding the sound tooth socket ⦿ Wider & more dense in teeth of heavy occlusion 8 4 12/15/2023 10 Thickening of lamina dura + Widening of PDL space 11 5 12/15/2023 Loss of lamina dura (Hyperparathyroidism) 12 Alveolar crest ⦿ ⦿ ⦿ ⦿ ⦿ ⦿ ⦿ The occlusal part of the alveolar bone that is composed of cortical bone. R-O line between teeth A point of bone in ant. teeth ; flat in post. CEJ to alveolar crest ... 1-2 mm Recede apically with age Markable resorption with periodontal disease Continuing with lamina dura and forms a sharp angle → Rounding angle indicates periodontal disease 13 6 12/15/2023 15 Alveolar bone ⦿ The bone that supports the tooth ⦿ Composed of cancellous and cortical bone 16 7 12/15/2023 Cancellous bone (trabecular bone or spongiosa) ⦿ Thin small R-O compartments (medullary spaces)separated by a RO honeycomb pattern(trabeculae) ⦿ Anteriorly: fine, granular & dense pattern, the marrow spaces are small and numerous. ⦿ Posteriorly: trabecular similar to ant., slightly larger in marrow spaces. 17 Cortical bone ⦿ Dense RO structure Comprises: ⦿ ⦿ The buccal and palatal plates of the maxilla and mandible Lamina dura and alveolar crest. 19 8 12/15/2023 Bone Loss 21 Horizontal Bone Loss 22 9 12/15/2023 Vertical bone loss (angular) 23 Vertical bone loss (angular) 24 10 12/15/2023 Maxilla 25 Anatomical Structures of the Maxilla 26 11 12/15/2023 MAXILLA RADIOLUCENT RADIO OPAQUE 1. 2. 3. 4. 5. 1. 2. 3. 4. 5. 6. 7. INTERMAXILLARY SUTURE NASAL FOSSA INCISIVE FORAMEN LATERAL FOSSA NASOLACRIMAL CANAL ANTERIOR NASAL SPINE NASAL SEPTUM FLOOR OF NASAL FOSSA NOSE FLOOR OF MAXILLARY SINUS ZYGOMATIC PROCESS MAXILLARY TUBEROSITY 27 Intermaxillary suture (median palatal suture) ➢ ➢ ➢ A R-L line in the midline of the Mx. from alveolar crest between the roots of the central incisors continues posteriorly the Mx. palatine processes to the post. aspect of hard palate. Limited by two R-O borders of thin cortical bone in each Mx 28 12 12/15/2023 Nasal fossa ▪ The paired R-L structure superior to the apices of the incisor teeth. ▪ The RO band that separates the rt and lf nasal fosa is nasal septum. ▪ It ends inferiorly in V-shaped RO anterior nasal spine ▪ The inferior border appears as a R-O line extending bilaterally away from the base of the anterior nasal spine. 29 Nasal septum ▪ R-O image arising in the midline from the ant. nasal spine , is a superimposition of septal cartilage & vomer bone. 30 13 12/15/2023 Incisive foramen (nasopalatine foramen) ▪ A small rounded or oval R-L between the roots of the Mx central incisors . ▪ Oral terminus of the nasopalatine canal transmits the nasopalatine vessels & nerves ▪ Incisive canal cyst : enlargement of the foramen & canal , > 1cm 31 Nose ▪ ▪ Superimposed on the anterior maxilla A slightly opaque appearance with sharp border 34 14 12/15/2023 Nasolacrimal canal ▪ Routinely seen on Maxillary occlusal projection in molar region . 35 Maxillary sinus ▪ An air-filled cavity with mucosa lining ▪ Three-sided pyramid, base & the medial wall adjacent to nasal cavity, apex extending laterally into zygomatic process of Mx. ▪ Bilateral symmetry 36 15 12/15/2023 37 ▪ Thin R-O line near apices of upper premolars & molars ▪ Enlarge during adult life in response to environmental factors (ex. missing teeth) Sinus pneumatization 38 16 12/15/2023 Maxillary sinus: 39 ▪Septa—folds of cortical bone projecting away from the floor and wall of the antrum, usually vertically oriented . Complete septa divide the sinus into individual compartment in 1-10% . 40 17 12/15/2023 In periapical radiographs of the canine, the floors of the sinus and nasal cavity are superimposed and seen crossing one another, forming an inverted “Y” in the area of the canine or premolar. ▪ ▪ Roots apices may cause small elevations into the floor of the sinus. 41 Zygomatic process and zygomatic bone ▪ ▪ ▪ Zygomatic process of the Mx: Extension of lateral Mx. surface, arises in the apical area of the 1st & 2nd molar, and articulates with the zygomatic bone. “U” shaped R-O line on the periapical radiographs. 42 18 12/15/2023 Zygomatic bone ▪ The inferior part of the zygomatic bone extends posteriorly from infer. border of the zygomatic process of Mx, a uniform white R-O over the apices of molars 44 45 19 12/15/2023 Coronoid process ▪ Frequently apparent on periapical film of the maxillary molars region ▪ A triangular R-O, with apex directed superiorly & anteriorly. 49 Anatomical Structures of the Mandible: 50 20 12/15/2023 RADIOLUCENT 1. SYMPHYSIS 2. MENTAL FOSSA 3. SUBMANDIBULAR GLAND FOSSA 4. MENTAL FORAMEN 5. MANDIBULAR CANAL 6. NUTRIENT CANALS RADIO OPAQUE 1. 2. 3. 4. 5. 6. GENIAL TUBERCLES MENTAL RIDGE MYLOHYOID RIDGE EXTERNAL OBLIQUE RIDGE INFERIOR BORDER CORONOID PROCESS 51 MANDIBLE Symphysis In infant, a R-L line through the midline of the jaw ▪ The suture usually fuses by the end of the first year of life, then no longer radiographically apparent. ▪ 52 21 12/15/2023 Genial tubercle ▪ Spine shaped bony protuberances ▪ Midline lingual surface of the mandible, above the inferior border. ▪ Well visualized on standard Md. occlusal film as one or more projections; as a R-O mass (3-4mm in diameter) in the midline below the incisor roots. 53 ▪ Lingual (spinous) foramen : A small R-L dot surrounded by the cortical wall of the termination of incisive branch of mandibular canal. 54 22 12/15/2023 Mental ridge ▪ R-O lines sweeping bilaterally forward and upward toward the midline on periapical film of the Md. central incisors. 55 Mandibular canal ▪ A dark linear shadow with thin R-O superior and inferior borders cast by the lamella of bone that bounds the canal ▪ Apparent between the mandibular foramen & the mental foramen and may close contact with all molars and 2nd premolar. 56 23 12/15/2023 Mental foramen ▪ Anterior limit of the inferior dental canal on the radiographs. ▪ Round, slit-like or very irregular and partial or completely corticated. ▪ Between the lower border of the mandible and the alveolar crest, usually in the apex of the 2nd premolar. 57 Nutrient canals ▪ R-L lines of fairly uniform width ▪ Running vertically from the inf. dental canal to the apex of tooth or into the interdental space between Md. incisors. ▪ Visible in 5 % patients, esp. in blacks, males, older persons, and individuals with high blood pressure or advanced perio. disease. 58 24 12/15/2023 Mylohyoid ridge (Internal oblique ridge) A bony crest on lingual surface of the mandibular body, attachment of mylohyoid muscle. ▪ Running downard and forward from the area of 3rd molar to premolar at the level of apices. ▪ 59 External oblique ridge ▪ ▪ A continuation of the ant. border of ramus → a line of attachment of buccinator m. A R-O line near the alveolar crest in the mandibular 3rd molar region. 60 25 12/15/2023 61 Submandibular gland fossa ▪ A depression immediately below the mylohyoid ridge in molar region, above the inferior border of the mandible ▪ Accommodates the submand. gland → a R-L area with sparse trabeculae , poorly defined anter. & posteriorly 62 26 12/15/2023 Inferior border of mandible ▪ A dense, broad, R-O band 63 Sequence for interpreting normal radiographic anatomy 64 27 12/15/2023 Restorative materials: 65 66 28 12/15/2023 Panoramic/ Orthopantomogram (OPG) Anatomy 67 How to interpret the panoramic radiograph ? 68 29 12/15/2023 Zone 2: TMJ Zone 3: Ramus & spine Zone 4: hyoid bone Zone 1:Nose & sinus Zone 6:teeth Zone 5:Inferior border of Mand. Zone 2: TMJ Zone 3: Ramus & spine Zone 4: hyoid bone 69 Types of Panoramic Images ➢Single Real Image ➢Double Real Image ➢Ghost Images 71 30 12/15/2023 Single Real Image Only one image results from a given anatomical structure. Most images seen on a panoramic film are of this type. 72 Double Real Image Two images of a single object which is located in the midline. Structures that produce these double real images include the hard & soft palate, hyoid bone and cervical spine. 73 31 12/15/2023 74 Ghost Image Usually caused by external objects such as earrings but may be produced by dense anatomical structures such as the mandible 75 32 12/15/2023 76 77 33 12/15/2023 Ghost Image: ▪ Opposite side ▪ Same shape ▪ Larger ▪ Projected higher on film ▪ Less distinct 78 79 34 12/15/2023 Landmarks 80 81 35 12/15/2023 30- Tuberosity 82 86 36 12/15/2023 2 1 4 3 1- hard palate 2- Floor of maxillary sinus 3- mental foramen 4- hyoid bone 88 2 3 4 1 5 1-ghost shadow of the mandible 2- condyle 3- Oral airway 6 4- tongue 5- mandibular canal 6- impacted third molar 89 37 12/15/2023 1 5 6 2 4 7 3 1- nasopharynx 5- hard palate 2- Uvula 3- posterior pharyngeal wall 6- soft palate 7- oropharynx 4- tongue 90 Thanks 91 ! 38