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
What bone of the skull forms the Posterior Portion & Floor, contains Foramen Magnum, and contains the Brainstem and Cerebellum?
Occipital Bone
What articulates with the articular facets of C1 (the Atlas) to form the atlanto-occipital joint?
The occipital condyles
What is a big floor and a holding place for the posterior side of the brain, the brainstem, and cerebellum?
Foramen magnum
What bone of the skull contributes to form the mid-floor and features greater wings and lesser wings?
Sphenoid Bone
What bone houses the most important part of our equilibrium and hearing?
Temporal Bone
What part of the Temporal Bone houses the inner ear (Labyrinth) and CN VIII which passes through the internal acoustic meatus?
Petrous Part
What holds the Internal Carotid artery?
Carotid Canal
What holds the CN VII (facial nerve)?
Stylomastoid Foramen
What parts make up the Temporal Bone in the cranial cavity?
- Squamous part
- Zygomatic part
- Petrous part
- External acoustic meatus
- Styloid process
- Mastoid process
The inner ear houses sensory receptors that are responsible for detecting what?
Equilibrium/vestibular sense
Audition/hearing (cochlea)
What senses changes in head position, includes 3 semicircular canals filled with fluid-angular head movements, and vestibule-static head positioning?
Equilibrium/vestibular sense
What bones vibrate every time you hear a sound?
Tympanic Membrane
What is the smallest bone in the body?
Stapes
What does the inner ear house that is responsible for detecting audition?
Sensory receptors; audition hearing (cochlea)
What helps us recognize when we’re moving up and down (i.e., going up and down in an elevator)?
Saccule
Utricle
What nerves in the inner ear form vestibulocochlear nerve (CN VIII)?
Vestibular nerve
Cochlear nerve
What bones make up the mandible?
Condylar process
Ramus
Angle
Mental foramen
Body
What bones make up the internal surface of the mandible?
Coronoid process
Lingula
Mandibular notch
Mandibular foramen (inferior alveolar foramen)
What articulates with the skull at the Temporomandibular Joint (TMJ), forms the lower jaw, and is a gliding hinge joint?
Mandible
What does the inferior alveolar nerve change into once it leaves the inferior alveolar foramen (Mandibular foramen) through the mandible and exits the mental foramen?
Mental Nerve
