Lecture 23 Flashcards
Visceral component of the skull
Bones around the mouth
Neural component of the skull
Bones protecting the brain
To what does “cranium” refer?
The skull minus the mandible
Viscerocranium
Formed by the union of the maxillary bones and the zygomatic bones
Neurocranium
- Formed by bones making “calvaria” (skull cap)
- Fused frontal bones, paired parietal bones, squamous portion of temporal bones, and occipital bones
- Separated by sutures
Inner table
- Compact bone
- Periosteuim attaches to dura mater
Outer table
- Compact bone
- Periosteuim attaches to scalp
Dipolë
- Cancellous bone
- Cancellous bones contains veins which are named for the area where they are located.
Ex: occipital
Sagittal suture
Separates the two parietal bones
Coronal suture
Separates the frontal bone from the parietal bones and helps form the “soft spot,” or “bregma”, in the infant
Lambdoidal suture
separates the occipital bone from the parietal bones
Metopic suture
Separates the frontal bones prior to their fusion around 6 or 8 months of age
Squamosal suture
Separates parietal from squamous portion of temporal bone
Small Wormian/Suture bones
- may be found lying within the sutures of individual calvaria bones
Diploic veins coursing within the dipolë
- Frontal veins
- Anterior temporal veins
- Posterior temporal veins
- Occipital veins
Emissary veins
May pierce the skull and connect the veins of the scalp with diploid veins and internal venous sinuses
The Orbit
Pyramid-shaped cavity which lies above the maxillary sinus and just lateral to the nasal cavity
Found within the Orbit-Farmaina
- Optic canal (nerve and artery)
- Superior orbital fissure
- Inferior orbital fissure
- Infraorbital groove
Borders of Orbit-Farmaina
Roof - frontal bone
Lateral side - Zygomatic bone
Floor/part of medial side: Maxillary bone
Medial side: Ethmoid bone
Medial side: Lacrimal bone
Orbital process of the palatine bone: Sphenoid bone and apex
Pterion
- Formed at juncture of coronal suture with greater wing of sphenoid
- Bone is thinnest here (“Temple”)
- Fracture at pterion damages middle meningeal artery
Bleeding from middle meningeal artery can result in…
Epidural hematoma (between dura mater and inner table of bone)
Middle meningeal artery supplies…
dura matter
Sphenoid bone
- greater wing, lesser wing, medial/lateral pterygoid plates, and body
- Body contains sphenoid sinus and hypophyseal fossa (sella turcica), housing pituitary gland
Sphenoid body includes…
- Hypophyseal fossa
- Posterior clinoids (anterior clinoids part of lesser wing)
- Sella Turcica
Frontal bone
- Forms the Orbital Plates
- Covers the Orbits
- Forms the forehead
- Contain the frontal lobes
Occipital Bone
- Forms the posterior portion & floor of the skull
- Contains the brainstem and cerebellum
Temporal bone
- Joins with parietal bone and greater wing of sphenoid to make lateral aspect of neurocranium.
Occipital bone parts
- Basilar part
- Occipital condyle
- Foramen magnum
Temporal bone parts
- Mastoid process
- External/Internal acoustic meadus
- Styloid process
- Squamous portion
- Petrous portion (houses inner ear)
- Zygomatic portion
Inner ear responsible for…
- Hearing (cochlea)
- Balance (semicircular canals)
- CN VIII (vestibulocochlear) carries these to brain
Three paired Cranial fossae
- Anterior cranial fossa
- Middle cranial fossa
- Posterior cranial fossa
Posterior cranial fossa
- Formed by occipital bones, small portion of parietal, and petrous portion of temporal bone
- Contains the cerebellum and brainstem
Middle cranial fossa
- Formed by petrous and squamous portions of temporal bone, and greater wing of sphenoid.
- The groove for the middle meningeal artery and body of sphenoid (w/ hypophyseal fossa)
- contains temporal lobes of cerebral cortex
Anterior cranial fossa
- Formed by lesser wing of sphenoid, orbital portion of frontal bone, and cribriform plate of ethmoid
- contains frontal lobes of the cerebral cortex
Crista galli
- “Rooster’s comb”
- protrudes up between cribriform plates
- attachment point for the dura mater
Mandible
- Lower jaw
- articulates w/ skull via temporomandibular joint (TMJ)
Temporomandibular joint
- formed by articulation of mandibular fossa and head of mandible
- Multiaxial joint: protrude, retract, elevate, and depress
Parts of mandible
- head
- neck
- mandibular notch
- coronoid process
- ramus
- angle
- body
- mental foramen
- mandibular foramen
- lingula (tongue)
Site for a dental block?
Mandibular foramen!
- Also, inferior alveolar nerve passes through and terminates as Mental Nerve
Scalp is composed of… (superficial to deep)
- Skin
- Connective tissue (dense; blood vessels and sensory nerve endings)
- Aponeurotic layer (galea aponeurotica)
- Loose connective tissue
- Periosteum
Parts of viscerocranium
- nasal bone
- lacrimal bone
- zygomatic bone
- maxillae
- inferior nasal conchae
- unpaired vomer
- palatine bone
Parts of neurocranium
- frontal bone
- parietal bone
- ethmoid bone
- sphenoid bone
- temporal bone
- occipital bone
