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
Which part of the temporal bone contains the zygomatic process?
Squamous portion of temporal bone
Which part of the temporal bone contains the attachement for the tentorium cerebelli?
Petrous (rock) portion of temporal bone
Which part of temporal bone encloses the internal carotid artery?
Petrous (rock) portion of temporal bone
What is unique about the temporal bone in a newborn skull?
It lacks a mastoid process
When flexed, in what direction does the temporal bone move? In extension?
Flexion: External rotation
Extension: Internal rotation
Internal rotation of the temporal bone causes what type of sound in a patient’s ear?
Causes high pitched tinnitus (d/t compression of the eustachian tube)
External rotation of the temporal bone causes what type of sound in a patient’s ear?
Causes a low pitched, swishing, or roaring tinnitus (eustachian tube is open)
During SBS flexion, how does the frontal bone move?
External rotation = lateral side moves anterior/lateral and slightly inferior, glabella moves posteriorly
During SBS extension, how does the frontal bone move?
Internal rotation = lateral side moves posterior/medially and slightly superior, glabella moves anteriorly
What type of synostosis results in the following:
- shorter and wider head (restriction of growth of anterior fossa)
- compensatory vertical growth (turricephaly)
- associated with Apert, Crouzon, Muenke, Pfeiffer, and Saethre-Chotzen syndromes
BICORONAL synostosis
What type of synostosis results in the following:
- a head shaped called anterior plagiocephaly
- face has a “C-shape” or “facial twist” deformity (base on nose towards affected side and tip of nose away)
- affected forehead is flat; contralateral forehead more anterior
- affected side ear more anterior
- d/t restricted anterior growth of top of skull and cranial base
UNICORONAL synostosis
