Paired Bones Lecture Flashcards
List the paired bones
- Parietal
- Temporal
- Nasal
- Zygomatic
- Maxilla
- Palatine
- Lacrimal
- Inferior nasal conchae bones
In general, during flexion (inhalation), the paired bones all rotate in what direction?
Externally
What 5 bones does the parietal bone articulate with?
- Occiput
- Frontal
- Sphenoid
- Temporal
- Opposite parietal
What is the Pterion?
Junction of 4 different bones
- Frontal
- Parietal
- Temporal
- Sphenoid
What is the Asterion?
Junction where three cranial sutures meet:
- Lambdoid
- Parieto-mastoid
- Occipito-mastoid
Or Where these three bones meet:
- Parietal
- Occipital
- Mastoid portion of temporal
What landmark of the parietal bone is the attachment point for temporal fascia?
Upper temporal ridge
What landmark of the parietal bone is the origin of the temporalis muscle?
Lower temporal ridge
What landmark of the parietal bone (and a bit the temporal bone too) is filled by the temporal muscle?
Temporalis fossae
What is the axis and the plane of motion of the parietal bones?
Axis: anterior-posterior axis
Plane of motion: coronal
What is the suture joining the two parietal bones?
What is the suture joining the parietal with the temporal bone?
Parietal + Parietal = Sagittal suture
Parietal + Temporal = Squamous suture
During flexion, in what direction do the parietal bones move?
“External rotation”
- the sagittal articulation moves inferiorly (down)
- the temporal articulation (squamous suture) moves laterally (out)
- cranium widens laterally (gets “short and fat”)
During extension, in what direction do the parietal bones move?
“Internal rotation”
- sagittal articulation moves superiorly (up)
- temporal articulations (squamous suture) moves medially (inward)
- cranium narrows laterally (gets “tall and skinny”)
What is cranial synostosis?
Premature closure of cranial sutures
What the most common type of synostosis and in what direction does it restrict growth?
Sagittal synostosis
– restricts the TRANSVERSE growth of skull
What type of synostosis results in the flattening of the back of the head on the affected side and ipsilateral compensatory growth of the mastoid?
Lambdoid synostosis