8. Skull and facial bones Flashcards
When imaging the nasal bones, how should you image and what two landmarks should you include?
Always bilateral imaging including the anterior nasal spine and nasion
What do the nasal bones articulate with?
- Other nasal bone
- Frontal bone (nasion)
- Maxillae
What is the smallest bone in the face?
Lacrimal bone
Where do the tear ducts pass through?
Each of the lacrimal bones
Where is the lacrimal bone located?
Posterior and lateral to nasal bones
What do the lacrimal bones form?
The anterior part of the medial wall of each orbit
What does the maxillary bones form?
(3)
- Part of the lateral walls and most of the floor of the nasal cavity
- Part of the floor of the orbits
- 1/4 of the hard palate
What is the hard palate and what is its function?
It is the bony roof of the mouth and separates the nasal cavity from the oral cavity and allows us to form a bolus
What is another name for the anterior nasal spine?
Acanthion
What are the four processes that come from the body of the maxillary?
- Frontal process
- Zygomatic process of the maxilla
- Alveolar process
- Palatine process
What bones articulate with the maxillary?
Every other facial bone exept the mandible
In a lateral image, how can you tell the left zygomatic process of the maxilla from the right?
The larger bone is closer, but in a lateral image, they should be superimposed
On a lateral skull, what anatomy do we use to asses the tilt of the skull?
Orbial plates of the frontal bone
(key word is skull)
Where is the inferior orbital fissue located?
Between the graeater wing of the sphenoid and maxilla
What are the landmarks located on the maxilla?
three
- Inferior orbital fissue
- Infraorbital foramen
- Maxillary branch of trigeminal nerve
On a lateral facial bone image, what structure to we look at to acess the tilt/rotation?
The zygomatic process
What forms the zygomatic arch?
The zygomatic process of the temporal bone and the temporal process of the zygomatic bone
What processes are formed by the zygomatic bones?
4
- Frontal process of zygomatic bone
- Temporal process of zygomatic bone
- Sphenoid process of zygomatic bone
- Maxillary process of zygomatic bone
What does the zygomatic bone articulate with?
4
- Frontal bone
- Temporal bone
- Sphenoid
- Maxillary
What is the function of the soft palate?
Closes the nasopharynx
Where does the palatine bones acessend?
Accends between the maxilla and the pterygoid processes of sphenoid
What does the palatine bone form?
Vertical-three
- The posterior nasal cavity
- Posteriomedial orbit (the tip)
- Posterior 1/4 of the hard palate
What do the inferior nasal conche form?
- Inferior lateral wall of the nasal cavity
What is the function of the 3 pairs of nasal conche?
Increase the surface area of the nasal cavity and help swirl and filter air before it passes into the lungs
What does the vomer form?
The inferior portion of the bony nasal septum
Which way does the vomer slide?
It slants superiorly and posteriorly from anterior nasal spine
What is the only moveable skull bone?
Mandible
Also the largest, strongest facial bone
What are the two parts of the mandible?
- Ramus-Vertical part
- Body-horizontal part
What is the place called where the ramus and body of the mandible meet?
Angle/Gonion
What 3 cranial bones make up the orbits?
- Frontal Bone
- Sphenoid
- Ethmoid
Where is the hyoid bone suspended
Be specific
Suspended from the styloid process (located on the tympanic portion) of the temporal bones by muscles and ligaments
What bone is located anteriorly between the mandible and the larynx?
The hyoid bone
What does the hyoid bone articulate with?
No other bone
What does the frontal process of the maxillae articulate with?
The nasal bone and the frontal bone
What does the zygomatic process of the maxillae articulate with?
The zygoma
What does the alveolar process articulate with?
8 teeth
What does the palatine process of the maxillae articulate with?
- Incisive foramen
What does the palatine process of maxillae form?
The anteiror 3/4 of the hard palate
What are the landmarks located on the ramus of the mandible?
- Mandibular condyle
- Coronoid process
- Mandibular notch
What does the mandibular condyle articulate with and what does it form?
The mandibular fossa of the Squamous portion of the temporal bone to form the TMJ
The coronoid process of the ramus on the mandible is the attchment for what muscle?
The temporalis muscle
Where is the mandibular notch located?
In the area between the coronoid process and the condyle of the mandible
What are the landmarks located on the body of the mandible?
4
- Alveolar process
- Symphsis menti
- Mental protuberance
- Mental foramen
Where is the mental foramen located?
Below the 2nd premolar/bicuspid tooth
What is C3 the landmark for?
The angle/gonoin of the mandible
What forms the circumfernce of the orbit?
3
- Frontal bone
- zygomatic bone
- Maxillary
What forms the floor of the orbit?
3
- Maxillary
- zygomatic
- Palatine
Where do blow out fractures occur?
At the floor of the orbit
What bones form the medial wall of the orbit?
- Ethmoid
- Lacrimal
- Maxillary
What forms the roof of the orbit?
2
- Mainly frontal bone (orbital plates)
- Lesser wing of sphenoid
What forms the lateral wall of the orbit?
- Frontal process of zygomatic
- Greater wing of sphenoid
What is the thickest and thinnest part of the orbital wall?
Thickest: Lateral wall of orbit
Thinnest: Medial wall of orbit
Where is the TMJ located in relation to the EAM and what type of joint(s) is it?
TMJ is anterior and slightly superior to the EAM. It is a synovial, diarthrosis joint as well as a hinge and gliding joint.
What is the term that describes the amount that the condyle moves?
Excursion
What does the mandibular condyle articulate with?
With the mandibular fossa of the zygomatic process of the tempral bone
Air filled structurees that all communicate with nasal cavity are called what?
The paranasal sinuses
What is the purpose of the paranasal sinuses?
4
- Resonating chamber for the boice
- Decrease weight of skull
- Help warm and moisten air inhaled
- Act as shock absorbers in trama
What is the most superior paranasal sinus?
The frontal sinus
Where is the frontal sinus located?
Between the 2 tables of squama
wut
Where are the sphenoid sinuses located?
In the body of the sphenoid
Have to open mouth to see on an AP
Where are the ethmoid sinuses located?
On the lateral masses of the ethmoid
What are the 3 different groups of ethmoid sinuses?
- Anterior
- Middle
- Posterior
What is the largest paranasal sinus?
The maxillary sinuses
Where is the maxillary sinus located?
The the body of the maxillae
What is the floor of the maxillary sinus called?
The maxillary antrum
In a frontal view of the maxillary, what shape does the maxillary sinus appear to be in? What about a lateral view?
Frontal: Appear pyrimid shaped
Lateral: Appear more cube shaped
Why do we tilt the head down when imaging maxillary?
To lower the petrus ridges to get them out of the way to see the fluid in the sinuses