Skull-Part 2 Flashcards
What is the location of the ethmoid bone?
Floor of cranium. Inferior to frontal bone and anterior to sphenoid (non-technically: centre of face, behind nose).
What are the articulations of the ethmoid?
Sphenoid, frontal, vomer, INC, lacrimal, nasals, palatines and maxillae.
What is the the location of the frontal bone?
Forehead, extending down to form the upper surface of the orbits. Anterior roof of the skull.
What are the articulations of the frontal bone?
Sphenoid, ethmoid, parietals, nasals, lacrimal, maxillae and zygomas
What is the location of the occipital bone?
Posterior wall and base of cranium.
What are the articulations of the occipital bone?
Parietals, temporals, sphenoid and atlas
What is the location of the parietal bone?
Form most of the superior part of the cranium
What are the articulatioins of the parietal bone?
Frontal, occipital, sphenoid and temporals
What is the location of the sphenoid bone?
Situated at base of cranium
What are the articulations of the sphenoid bone?
All cranial bones, pterygoid processes with vomer and palatine
What is the location of the temporal bone in relation to the skull and the sphenoidal wings (greater)?
Lateral aspect of skull, posterior to the greater sphenoidal wings
What are the articulations of the temporal bone?
Sphenoid, parietals, occipital, mandible, and zygomas
What is the anterior cranial fossa made of?
Made of frontal bone, ethmoid, lesser wing of sphenoid
What is the Middle cranial fossa made of?
Sphenoid, temporal bones
What is the Posterior cranial fossa made of?
Jugular foramen, occipital, foramen magnum
What structures are located within the middle cranial fossa?
Temporal lobe of the cerebrum, the pituitary gland, optic nerves and chiasm, cavenours sinus, hypothalamus and internal carotid artery
What is another name for the posterior cranial fossa?
infratentorial fossa
What structures are contained within the anterior crainial fossa?
Fronal lobes of the cerebrum and olfactory bulbs
What structures are contained within the posterior crainial fossa?
Cerebellum, pons, medulla oblongata, midbrain, some crainial nerves
What bone is this describing?
Forms part of the sides and base of the cranium
Temporal bone
What are the different portions of the temporal bones?
Divided into squamous, tympanic, mastoid and petrous portions
What portion of the temporal bone projects upwards to form parts of the sides of the cranium?
Thin squamous portion projects upwards to form parts of the sides of the cranium
What bone extends anteriorly from the squamous portion of the temporal bone?
The zygomatic process
What does the zygomatic process form?
Forms part of the zygomatic arch
What forms the anterior boundary of the mandibular fossa?
Articular eminence at the base of the process forms the anterior boundary of the mandibular fossa (groove in the temporal bone)
Where does the tympanic portion of the temporal bone lie? What does it form?
Lies below the squamous portion and forms the majority of the EAM.
Where is the mastoid process of the temporal bone located in relation to the typanic portion?
Located just posterior to the tympanic portion
What is the prominent conical region on the temporal bone called?
Mastoid process
Mastoid process provides a site of attachment for the ? muscle.
Sternocleidomastoid
What structures does the mastoid process enclose?
The mastoid process encloses the mastoid air cells and mastoid antrum
What is the Mastoid antrum?
Air filled cavity that communicates between the mastoid air cells and the middle ear (tympanic cavity
Where is the petrous portion of the temporal bone situated in relation to the sphenoid and occipital bones?
Situated at an angle between the sphenoid and occipital bones
What does the posterior surface of the petrous pyramid form?
Forms the anterior bony limit of the posterior fossa
What canal is located near the center of the posterior surface of the petrous pyramid?
Internal auditory canal
What does the interior of the petrous pyramid house?
The delicate middle and inner ear structures
T/F
Other openings associated with the petrous pyramid are the jugular foramen (IJV) and carotid canal (ICA).
True
What does the inferior surface of the petrous pyramid give rise to?
The styloid process
What is the styloid process attached to?
Attached to several muscles of the tongue and ligaments of the hyoid bone
What fills up the mastoid process?
Mastoid air cells filling up the mastoid process
What structure is located anterior to mastoid air cells?
EAM
What structure is located deep to the EAM?
Deeper you see the tympanic cavity
Where is the jugular foramen located?
Located on the posterior side of the petrous pyramid
Where is the canal which houses the carotid artery allocated?
-On the anterior side of the pyramid (once it enters the skull its running through the pyramids on the anterior portion)
Where is the EAM located in relation to the TMJ?
Posterior to the TMJ is the EAM
What is the cartilaginous structure of the ear called
The oracle
What does the posterior wall of the mandibular fossa (made of temp bone) form?
The anterior wall of the EAC and the anterior wall of the mastoid air cells
As we move in from the EAC, there is a narrowing in the EAC between the two bony portions. What is this called?
This is known as the isthmus of the EAC
What separates the middle ear from the EAM
Tympanic membrane
What does the Tympanic membrane extend from? In what direction?
Extends anteriorly from the scutum (this is what the tympanic membrane attaches to)
T/F
Posterior side of the petrous ridge is the jugular foramen
True
Where is the opening into the internal auditory canal located?
On top of that petrous ridge on the posterior side is the opening into the internal auditory canal
T/F
If you follow the petrous ridge you follow the path of the internal carotid artery
True
What is the Tympanic annulus?
-Thin membrane separates the EAC from the tympanic portion of the bone
What muscle is this describing?
Broad, fan-shaped and is one of several chewing muscles that is necessary for crushing and grinding objects between the molars.
Temporalis muscle
What does the Temporalis muscle originate from?
It originates from the temporal fossa
Where does the Temporalis muscle pass in relation to the zygomatic arch?
Passes medially to the zygomatic arch
Where is the insertion for the Temporalis muscle?
Mandible’s coronoid process.
Where does the sphenoid bone extend within the cranial fossa?
Extends completely across the floor of the middle cranial fossa
What bone forms the majority of the base of the skull?
sphenoid bone
T/F
The sphenoid bone articulates with all the cranial bones
True
What portions does the sphenoid bone consist of?
body + greater wings (2) + lesser wings (2)
What is the Sella turcica?
Depression within the body of the sphenoid that houses the pituitary gland
What is the sella turcica bounded by anteriorly?
By the tuberculum sella
What is the sella turcica bounded by posteriorly?
Posteriorly by the dorsum sellae
What does the dorsum sellae give rise to?
The posterior clinoid processes
Fill in the blank:
The slanted area of the bone posterior and inferior to the posterior clinoid processes is continuous with the basilar portion of the occipital bone and is called the ?
Clivus
What do the pons sit against?
The clivus
Directly below the sella turcica are two air filled cavities called what?
The sphenoid sinuses
What divides the sphenoid sinus?
divided by the sphenoid septum (divide into 2 portions)
T/F
The Optic nerve travels posteriorly through the sphenoid through the optic foramen
True
What forms the anterior clinoid process?
Triangular shaped lesser wings attach to the superior aspect of the body to form the anterior clinoid process
What does the lesser wing provide passage for?
The optic nerve and ophthalmic artery.
Where do the great wings extend?
Laterally from the sides of the body
What do the sides of the body of the sphenoid contain?
Contain 3 paired foramina – rotundum, ovale and spinosum
What does the 3 paired foramina within the sphenoid contain?
Nerves and blood vessels
What structure extends from the inferior surface of the greater wing?
The pterygoid process
What is the pterygoid process divided into?
Divided into medial and lateral pterygoid plates
What bone serves as attachments for pterygoid muscles used in the movement of the lower jaw?
The sphenoid bone
What side is longer of the pterygoid process? The lateral or the medial?
Medial is longer
What structure is located on the medial side of the sphenoid bone that is hook shaped?
A pterygoid called the Hamulus.
What does the pterygoid processes articulate with to form part of the nasal cavity?
The palatine bone
What is located in the space between the greater wing and the lesser?
The superior orbital fissure
What portion of the sphenoid contributes to the lateral wall of the orbit?
The greater wing of the sphenoid
T/F
On the medial side of sphenoid you should see the optic canal
True
T/F
Just above the nasopharynx is the sphenoid sinus
True
Watch the following video:
https://youtu.be/UXTvNCV09Uo
What bone forms the posterior cranial fossa?
Occipital bone
Where is the foramen magnum located in relation to the brainstem and spinal cord?
At the junction of the brainstem and spinal cord
Occipital condyles project inferiorly to articulate with what?
The C1 (atlas) at the atlanto-occipital joint.
Which way does the anterior margin of the foramen magnum slope?
Slopes superiorly and anteriorly to meet with the clivus.
What does the Basilar artery run between?
Runs between the pons and the clivus
What are the two portions of the frontal bone?
Vertical + Horizontal portion
What portion of the frontal bone forms the forehead?
The vertical portion
What portion of the frontal bone contains the frontal sinuses?
Vertical portion
Supraciliary arches are joined to each other by a smooth area termed what?
Glabella
What is the roof of each orbit called?
Termed the orbital plate
What portion of the frontal bone is the orbital plate located in?
Horizontal portion
What portion of the frontal bone contains the majority of anterior cranial fossa?
Horizontal portion
What is the Supraorbital foramen?
The passage of supraorbital nerve located within the Horizontal portion of the frontal bone
T/F
Ethmoidal notch receives the horizontal portion of the ethmoid bone
False; Ethmoidal notch receives the CRIBIFORM PLATE of the ethmoid bone
How many Parietal bones are there?
2 Parietal bones
What does the parietal bone form?
Form the roof of the cranium and a little bit of the sides as well
What are the sutures of the skull?
Sagittal suture
Coronal suture
Lambdoidal suture
What is the superior point between the parietal bones called?
The vertex (which is the highest point of the cranium)
Where do the 2 parietal bones meet?
Meet at the midline sagittal suture.
