Unit 3_The Skull, Inner Ear & Mandible Flashcards
How many bones are attached to each other by sutures?
22
True or false, bones are attached to each other by sutures in infants?
False - bones attach to each other by sutures with growth
How many bones are included in the Neurocranium compartment?
8
How many bones are included in the Viscerocranium (facial skeleton)?
14
What bony compartment of the skull includes the brain and neurological components?
Neurocranium
What bony compartment of the skull includes expression, eating, speech, breathing, etc?
Viscerocranium
What are the bones of the skull?
- 2 Parietal Bones
- Sphenoid Bone
- 2 Temporal Bones
- Maxilla
- 2 Lacrimal Bones
- 2 Nasal Bones
- Frontal Bone
- Ethmoid Bone
- 2 Zygomatic Bones
- Occipital Bone
- Mandible
- Palatine Bone
- Vomer
- Sutural Bone (Wormian)
- 2 Inferior Nasal Conchae
What bones of the skull don’t have sutures?
- Frontal Bone
- Maxilla
What separates the 2 Parietal bones?
Sagittal Suture
What is protection for the brain?
The Skull
What separates the cranial bones?
Fibrous Sutures form Fibrous Joints
Sutures become ossified with age (Synostosis)
What are three fibrous skull sutures that form fibrous joints?
Coronal Suture
Sagittal Suture (Ss)
Lambdoid Suture (LS)
What are non-named bones that are unique to an individual?
Sutural Bone (Wormian) (Wb)
What are large unossified gaps between bones filled with fibrous tissue that close in the first year of birth?
Fontanelles
What portion of the skull is bigger in newborns and levels out with age?
Neurocranium
What drains de oxygenated blood, the neurocranium and the scalp into the dural venous sinuses?
Diploic Veins
What are the orbit-pyramidal shaped socket contributing bones?
Boundaries:
- Roof - Frontal Bone
- Medial Wall - Lacrimal, Ethmoid bone (Orbital Plate)
- Lateral Wall - Zygomatic Bone
- Floor (Inferior) - Maxilla
- Apex - Greater wing-sphenoid
Openings:
- Optic Canal
- Superior Orbital Fissure
- Inferior Orbital Fissure
- Infraorbital Groove
What is the meeting place for the frontal, parietal, temporal, and sphenoid bones? It’s also a weak (vulnerable) spot due to “skull thinness”?
The Pterion
What artery is behind the Pterion?
The Middle Meningeal Artery and its branches lie in the epidural space:
- The anterior branch of the Middle Meningeal Artery (deep to the Pterion)
- The posterior branch of the Middle Meningeal Artery
What can form in the space between the Dura mater and the bones of the skull where the middle meningeal artery is positioned?
Hematoma; often fatal - 15-20%
What structures of the brain are included in the anterior cranial fossa of the cranial cavity/vault?
- Frontal lobes of the cerebral cortex
- Lesser wing of Sphenoid bone
- Orbital plates of Frontal bone
- Cribriform plates of Ethmoid bone & Crista Galli
What structures of the brain are included in the middle cranial fossa of the cranial cavity/vault?
- Temporal lobes of the cerebral cortex
- Greater wing of sphenoid bone
- Parietal bone & squamous part-temporal bone
- Petrous part-temporal bone
What structures of the brain are included in the posterior cranial fossa of the cranial cavity/vault?
- Cerebellum and Brainstem
- Occipital bone
- Petrous part of the temporal bone
- Parietal bone
What bone of the skull forms the Orbital Plates, covers the Orbits, forms the Forehead, and contains the Frontal Lobes-Cerebral Cortex?
Frontal Bone