Head/Neck--Skull And Face Flashcards
Bones of the head (skull)
- composed of 22 bones
- bones are fused by immovable joints
- mandible is the only movable bone
Neurocranium (cranium)
- supports and protects brain
- made of 8 large “flat” bones
Viscerocranium
- facial skeleton
- made up of 14 irregularly shaped bones
- make up face including nasal cavity, oral cavity, and orbits
Be able to identify cranial bones
1) frontal bone
2) parietal bone (2)
3) temporal bone (2)
4) occipital bone
5) sphenoid bone
6) ethmoid bone
Frontal bone
- large bone makes up forehead and roof of the orbit
- forms the supraorbital margin
Parietal bone
- 2 large bones make up the “sides” of the cranium
- articulate with each other in the midline
Temporal bones
Large irregular bones formed from 4 parts
1) squamous (flat part)
2) zygomatic (bridge)
3) tympanic (ear canal)
4) mastoid process
5) petrous (“rock” internal, contains inner ear)
Occipital bone
- Large bone forms the posterior and inferior aspect of the cranium
- contains large opening (foreaman magnum) for the spinal cord
Sphenoid bone
- wedge-shaped bone; butterfly
- the central portion of cavity floor contacts with the frontal, temporal, and parietal bones of the cranium
- **vulnerable to lateral skull fx
Ethmoid bone
- an irregularly-shaped spongy bone that contributes to the anterior cranial fossa
- forms the roof of the nasal cavity
- has Cribriform plate (sieve plate) where olfactory nerves run through
- part of nasal septum and lateral nasal wall
Sutures
- areas on the cranium that mark the joints between the bones of the skulls; immovable joints
- joining of sutures bregma and lambda are used as landmarks (stereotactic atlas) for brain surgery
Sagittal suture
Located between the parietal bones
Coronal suture
Between frontal and parietal bones
Lambdoid suture
Between parietal and occipital bones
Bregma
The junction of Sagittarius and coronal sutures
Lambda
The junction of sagittal and lambdoidal sutures
Fontanelles
- “soft” spots
- feature of the infant skull soft membranous gaps (sutures)between the cranial bones.
- anterior (bregma)
- posterior (lambda)
Cranial vault (floor)
- divided into 3 shelf-like regions
1) anterior cranial fossa: lies over the orbit, shallowest
2) middle cranial fossa: central depression houses pit gland
3) posterior cranial fossa: deepest and most posterior
Associations of cranial fossae with brain regions
1) anterior (frontal lobe of brain)
2) middle (temporal lobe of brain)
3) posterior (cerebellum, pons of brain)
Which bones compose the anterior fossa of cranial vault
- frontal
- sphenoid
- ethmoid
Which bones compose the middle fossa of the cranial vault
- sphenoid
- temporal
- **middle depression (pit gland)