Anatomy Flashcards
What is lamina dura?
teeth sockets are bounded by thin radiopaque layer of dense bone
– continues over crest of alveolar bone
What is alveolar crest? Where?
gingival margin of alveolar process between teeth (radiopaque line)
*continuous with lamina dura
– 1-2mm from crown/CEJ
What is the periodontal ligament space?
radiolucent space between the tooth root & lamina dura
*the constant pressure to bone surrounding root makes it more sclerotic/dense
What can a double PDL mean?
- convexity of proximal root surface
- two roots
What is cancellous/trabecular bone?
between cortical plates in both jaws
What pathologies can alter bone metabolism/trabeculation?
anemia, osteonecrosis, osteopetrosis
What is the anterior nasal spine?
- radiopacity at or just below junction of inferior end of nasal septum & inferior outline of nasal aperture
What structure meets at the anterior nasal spine?
floor of nasal cavity
What structure is superior to anterior nasal spine?
nasal septum
What is the intermaxillary suture?
“median suture”
- extends from alveolar crest between 8&9 posteriorly to distal aspect of hard palate
- uniform width
- variable shape (xray angulation)
What is the nasopalatine canal? What & where is the entrance? Exit?
- transmits nasopalatine nerves & vessels
- superior/Stenson foramina: usually 2 round/oval foramina in floor of nasal cavity
- incisive foramen (oral opening)
What is the incisive foramen?
- oral end of nasopalatine canal
- between 8 & 9 (if xray technique proper)
- variable size/shape
What is the nasal cavity?
located above oral cavity
- floor seen as thin radiopaque line
- inverted V in anterior region & straight line in posterior
Where do we typically see the intersection of the floor of the maxillary sinus & nasal cavity?
premolar level
What is the maxillary sinus?
- air-containing cavity lined with mucous membrane
- borders appear in PA radiographs as thin, irregular radiopaque lines
- may have septae
How does the nose appear in radiographs?
- soft tissue tip can be seen in projections of maxillary incisors superimposed over roots
- radiopaque entity
What is the lateral fossa?
– depression of maxilla near apex of lateral incisor
- diffuse radiolucency
What is the nasolacrimal canal?
- runs from orbit inferiorly to nasal cavity
**should NOT be seen in regular/good PA
Where can the nasolacrimal canal be seen? What shape?
- occasionally near apex of maxillary canine when steep vertical angulation is used (PA)
- lateral to maxillary molar; oval (occlusal)
What is the zygomatic process of the maxilla?
- radiopaque extension of the lateral maxillary surface that articulates with the maxillary process of the zygoma
What shape is the zygomatic process of the maxilla on a radiograph?
U shaped
What is the posterior extension of the zygomatic process of the maxilla?
- zygomatic bone
What is the nasolabial fold?
- oblique line demarcating a region that appears to be covered by a veil of slight radiolucency
- often traverses PA radiographs near premolar region
What is the pterygoid plates & hamular process?
- medial & lateral plates lie immediately posterior to tuberosity of maxilla
- process extends inferiorly from medial plate
What is the tuberosity?
- most posterior part of maxilla/alveolar bone
What is the mandibular symphysis?
- in infants
- radiolucent line through midline of jaw between forming deciduous central incisors
What are the genial tubercles?
radiopaque bony protuberances located on lingual surface of mandible slightly above inferior border & midline
What is the lingual foramen?
- foramen on lingual surface of midline of mandible in region of genial tubercles
*often two or more
What is the mental ridge?
- on PA of mandibular CI
- two radiopaque lines forming inverted V towards midline
- anterior surfaces of mandible
What is the mental fossa?
- depression on labial aspect of mandible
- extends laterally from midline & above mental ridge
How does the mental fossa appear on radiographs?
- ill-defined radiolucency in region of mandibular incisor roots
- PDL & lamina dura intact
What is the mental foramen?
- usually anterior limit of inferior dental canal
Where is the mental foramen found?
- area of canine to 1st molar
**can look like PARL…always look for intact lamina dura & PDL // no caries
What is the mandibular canal?
- dark linear shadow with thin radiopaque superior & inferior borders
Where is the mandibular canal?
- posterior to mental foramen… posterior to canine/premolar region
What are nutrient canals?
- carry neurovascular bundle & appear as radiolucent lines of fairly uniform width
*vertical/up and down OR round in cross-section
When is it common to see nutrient canals?
**perio dx
& in anterior mandible easiest
What is the internal oblique ridge/mylohyoid ridge?
- slightly irregular crest of bone on lingual surface of mandibular body
How should the mylohyoid ridge appear on radigraphs?
- anterior portion far from teeth & angles closer to teeth & alveolar bone in posterior position
What is the submandibular gland fossa?
- depression of bone on lingual surface of mandibular body
- immediately below internal oblique ridge in molar region
How to distinguish between mandibular canal & submandibular gland fossa?
- canal = well defined & is corticated
- fossa = ill-defined borders & not corticated
What is the external oblique ridge?
- continuation of anterior border of mandibular ramus
What is the inferior border of the mandible?
- occasionally seen on PA as dense, broad radiopaque band of bone
What is the coronoid process?
- triangular radiopacity
- apex directed superiorly & anteriorly
- superimposed on maxillary 3rd molar region
What is mandibular tori?
- bony outgrowths on lingual surface of mandible
- often bilingual & symmetrical
