Skull And Its Landmarks Flashcards
What are the 2 sections of the skull?
Neurocranium - 8 cranial bones
Viscerocranium - 14 facial bones
What is the function of the neurocranium?
- Protection (of brain)
- Attachment sites for origin and insertion of muscles of facial expression and mastication
- Framework for cranial and orbital cavities
Where does the Broca’s area lie?
Left frontal lobe
What is Broca’s aphasia?
Damage to the Broca’s area causing difficultly moving tongue or facial muscles. The individual can still read and understand spoken language but has difficultly speaking and writing.
Where does the Wernicke’s area lie?
Left temporal lobe
What is Wernicke’s aphasia?
Damage to the Wernicke’s area causing individuals to speak in long sentences that have no meaning. They can make speech but have difficulties in understanding speech.
What is a cranial suture?
Specialised fibrous connective tissue that connect cranial bones
What are the 5 main cranial sutures?
Coronal
Sagittal
Lambdoid
Squamosal
Metopic
Where is the coronal suture located?
Unites the frontal bone with the parietal bones (where the crown sits)
Where is the sagittal suture located?
On top of the skull and unites the left and right parietal bones in the midline
Where is the lambdoid suture located?
Back of skull and unites the left and right parietal bones with the occipital bones. (Upside down V shape)
Where is the squamosal suture located?
Side of skull and unites the squamous portion of the temporal bone with the parietal bones.
Where is the metopic suture located?
If present, it’s at the font of the skull and unites the two frontal bones.
What are the 8 cranial bones?
Sphenoid (1)
Temporal (2)
Ethmoid (1)
Parietal (2)
Occipital (1)
Frontal (1)
What type of bone is the frontal bone?
Flat bone
Functions of the frontal bone?
Provides structure to skull, eye orbits and upper face.
Protects frontal lobe
Aids in facial expressions (frontalis muscle attaches to frontal bone)
Where is the frontal bone located?
Front of cranium
What type of bone is the parietal bones?
Flat bone
Functions of parietal bones?
Provide structure and protection to cranial cavity
Protect parietal lobe
Where are the parietal bones located?
Superior and lateral walls of cranium
(Top of head)
What type of bone is the occipital bone?
Flat bone
What is the function of occipital bone?
Provides structure to the skill
Provides attachment for muscles
Protects occipital lobe
Forms the foramen magnum (opening that connects brain to spinal cord)
What’s the location of the occipital bone?
Back of skull
What type of bone is the temporal bones?
Irregular
What is the function of the temporal bone?
Provide structure to the skill and protection brain
The styloid process is an attachment point for muscles (tongue and larynx)
Contain middle and inner part of ear
Forms part of temporomandibular joint
Where is the temporal bone located?
Pairs of bones on side of head
What is the function of the viscerocranium?
Provides structure and support for soft tissues of the face and houses the teeth
What bone type is the ethmoid bone?
Unpaired, spongy and lightweight irregular bone
Where is the ethmoid bone located?
Situated in the paranasal sinuses, at the roof of the nasal cavity, between the eye sockets.
What does the ethmoid bone help form?
Nasal septum
Roof and lateral walls of nose
Mesial wall of orbital cavity
What are the four parts of the ethmoid bone?
Cribriform plate x1
Perpendicular plate x1
Ethmoid labyrinths x2
What is the cribriform plate?
Part of the ethmoid bone that forms the roof of the nasal cavity and is perforated by numerous olfactory fibres to allow nerves to pass through
What is the perpendicular plate?
Part of the ethmoid bone; thin, quadrilateral plate that forms the superior two thirds of the nasal septum, descends in the midline from the cribriform plate.
What are ethmoid labyrinths?
Large masses located either side of perpendicular plate; contain ethmoid air cells (sinuses)
What can fracture of the cribriform plate cause?
Anosmia (loss of smell)
What can a ethmoid labyrinth fracture cause?
Communication between nasal cavity and orbit (orbital emphysema)
What type of bone is the sphenoid bone?
Unpaired, irregular bone.
What is the structure of the sphenoid bone?
1x body
2x lesser wings
2x greater wings
2x pterygoid processes
Where is the pituitary gland housed?
Hypophyseal (Stella turcica); bony depression in sphenoid bone
What’s a foramen?
Opening or gap in bone that allows nerves and blood vessels to travel through
Where are the foramina in the sphenoid bone?
3 in each greater wing
Rotundum
Ovale
Spinosum
What part of sphenoid bone do the muscles of mastication attach?
Lateral pterygoid plate
What does the sphenoid bone contribute too?
Nasal cavity
Mesial wall of optic canal
Middle cranial fossa
Base and natural sides of skull
Orbital floor
What are the 2 pterygoid processes of the sphenoid bone?
Lateral pterygoid plate - attachment of MoM
Medial pterygoid plate - posterior opening of nasal cavity
What foramen carries the maxillary division of the trigeminal nerve?
Rotundum
What foramen carries the mandibular division of the trigeminal nerve?
Ovale
What foramen carries the middle meningeal vessels and the meningeal branch of the mandibular division of the trigeminal nerve?
Spinosum
What is the function of the viscerocranium?
Protect brain
House and protect sense organs
Provides framework for the soft tissues of the face
Facilitate; eating, facial expression, breathing and speech
Form of face
What are the 14 facial bones?
Vomer x1
Inferior nasal Conchae x2
Nasal bones x2
Maxilla x2
Mandible x1
Palatine bones x2
Zygomatic bones x2
Lacrimal bones x2
Function of the nasal bones?
2 slender oblong facial bones that form the shape of the nose
Function of the inferior concha?
Increase the surface area of nasal cavity to increased the amount of inspired air that contacts the mucous membrane within nose; filters, warms and humidifies the air.
What is the vomer bone?
Thin, singular, facial bone that runs vertically down nose, forms nasal septum
What are the lacrimal bones?
Paired facial bone and the smallest
Forms the most anterior part of medial wall of the orbit
Supports eyes
Part of nasolacrimal duct
What are the maxilla bones?
2 irregular shaped bones fused together by the intermaxillary suture
What do the maxilla bones form?
Maxillary dental arch (hold teeth)
Mesial border of orbit
Side of nasal cavity
What are the zygomatic bones?
2 irregular diamond shaped facial bones that form the cheek bones
What do the zygomatic bones provide and contribute to?
An attachment point for the masseter muscle
Contribute to; zygomatic arch, walls of temporal and infra-temporal fossa, floor and lateral walls of bony orbit.
What does the mandible form and what’s are its functions?
Lower jaw and jaw line
Houses the lower set of teeth
Assists in mastication and speech
What is the mandible composed of?
Body of mandible and ramus
What 2 bones from the temporomandibular joint?
Temporal and mandible bone
What are the palatine bones?
2 paired L shape facial bones that help form the hard palate, nasal cavity and eye socket
What nerves do the palatine bones house?
Lesser and greater palatine
Where is the palatine bone located?
At the back of the nasal cavity, between the maxilla and pterygoid process of sphenoid bone
What are torus palatinus?
Painless, hard bony lumps on the palate caused from overgrowth of palatine bone.
Can impede speech and eating.
What is the inferior concha?
Smallest facial bone and found inside the nasal cavity
What is the orbit?
Cavity that surrounds and provides mechanical protection to the eye and soft tissue surrounding
How many and which bones form the orbit?
7 (3 cranial and 4 facial)
Sphenoid
Ethmoid
Frontal
Zygomatic
Lacrimal
Maxilla
Palatine
What is a fossa?
Shallow depression
What are the 3 intracranial fossae?
Anterior cranial fossa
Middle cranial fossa
Posterior cranial fossa
What nerve runs through the ethmoid bone?
Olfactory nerve - smell
Which inter-cranial fossa is located centrally in the cranial floor?
Middle cranial fossa
Which inter-cranial fossa is most shallow and superior of the cranial fossae and accommodates part of the frontal lobe?
Anterior cranial fossa
Which cranial fossa accommodates the temporal lobes of the brain and what are they responsible for?
Middle cranial fossa
Responsible for;
Understanding language
Memory
Hearing
Organisation
What is the slender u shaped bones that lies just below the mandible?
Hyoid bone
What are the functions of the hyoid bone?
It aids the tongue in movement and swallowing
Holds up the larynx
Which cranial fossa is the deepest, accommodates brain stem and cerebellum?
Posterior cranial fossa
Which fossa contains the muscles of mastication?
Infratemporal fossa
Where is the infratemporal fossa located?
Irregular shaped cavity below and medial to zygomatic arch
Which muscles originate and insert at the borders of the infratemporal fossa?
Masseter and temporalis
Which muscles are within the infratemporal fossa?
Lateral and medial pterygoid muscle
Which division of nerve does the infratemporal fossa carry?
Posterior division of mandibular nerve
(ID blocks)
Which division of nerve does the pterygopalatine fossa carry?
Maxillary division; enters through rotundum foramen
(Maxillary infiltrations)
Which fossa has walls formed by the maxilla, palatine and sphenoid bones?
Pterygopalatine fossa