WK 3 Skull - Facial bones and sinuses

Major Bony features of the Facial bones

Maxillae (R and L Maxilla bones)

  • Maxillae: creates part of the orbital floor, medial wall of orbits, lateral wall of the nose and roof of the mouth

  • Maxillary sinus - biggest air sinuses and fractures can be seen

  • Maxillae had canine eminence, incisor fossa and canine fossa

  • Alveolar plate has teeth and roots embedded into it - raised up portion above the incisor tooth is the incisor fossa

  • floor of nose is the roof of the mouth

  • Anterior nasal spine helps to hold the nasal cartilage and septum in place - seen in lateral images, is also the acanthion

Zygomatic bones

  • Form the lateral wall and part of the floor of the orbit

  • Had temporal border and orbital border

Mandible

  • Symphysis Mentee - cartilage becomes ossified

  • Condyles form the TMJ

  • TMJ is a modified condylar hinge joint as it allows medial and lateral movement (grinding of food). Also protrudes and detrudes

Nasal bone

  • has internasal suture, frontonasal suture and frontomaxillary suture

Lacrimal

  • has fossa for the lacrimal gland which produces tears

Vomer

  • V shaped - pointy side pointing anterior and wider side is posterior

Palatine bone

3 portions

  1. Palatine portion of the palatine bone

  2. Nasal portion of the palatine bone: going up the lateral aspect of each nasal cavity

  3. Orbital part of palatine bone

  • Forms part of posterior orbital floor

Inferior nasal conchae

  • covers lower part of the opening into the maxillary sinus

Orbital margins

  • Roof: frontal bone

  • Lateral wall: zygomatic bone

  • Medial wall: maxilla, lacrimal, ethmoid and palatine bone (orbital part)

  • Floor: zygomatic bone and the maxilla

  • Optical canal of the sphenoid bone and optic nerve comes through there to connect to the back of the eyeball

  • Superior orbital fissure between the greater and lesser wing of sphenoid

  • Inferior orbital fissure between the maxilla and greater wing of sphenoid - allows things to pass down from the lower face region and not through the orbit

Le fort fractures

Type 1

  • fracture through the maxillae plate and removing the alveolar plate from the rest of the face - bottom of teeth and maxillae become disassociated with the face

Type 2

  • Full removal of maxillae from the zygomatic, nasal and frontal bones

Type 3

  • Same as type 2 but the zygomas are gone too - entire facial bones removed from cranium