W19/L4 + L10: Skull anatomy Flashcards
What is the upper part of the cranium called
The vault
What are the three layers of all of the bones of the skull?
External & internal layers of compact bone, with a middle layer of spongy bone (the diploe)
What are the skull sutures?
Immobile joint between the seperate bones
Name the four “main” sutures
Coronal
Saggital
Lamboid
Pterion
What bones form the coronal suture?
Frontal bone and the 2 parietal bones
What bones form the saggital suture?
The two parietal bones
<p>What bones form the lambdoid suture?</p>
<p>The two parietal bones and the occipital bone</p>
Which two sutures are in the coronal plane?
Coronal & lamboid
What bones form the pterion?
Frontal
Parietal
Temporal
Sphenoid
What is the significance of the pterion?
The bones are thin at this point, making it a site of weakness
The middle meningeal artery runs directly deep to the pterion
What are the 2 parts of the frontal bone?
The vertical part (forehead)
The horizontal part (forming the anterior cranial fossa and roof of the orbit)
What is the line of demarcation between the 2 parts of the frontal bone?
The supraorbital margins
Describe the parietal bone
Flat, rectangular bone moulded to brain contour
Describe the features of the occipital bone
Flat, moulded to posterior aspect of brain
Prominent external occipital protuberance
What are the 4 processes of the temporal bone?
Zygomatic
Mastoid
Styloid
Petrous
What is the flat “body” of the temporal bone called?
The squamous part
Describe the zygomatic process
A thin, forward projection that articulates with the zygomatic bone
Describe the mastoid process
A thick, chunky, downwards projection
Describe the styloid process
Deep, sharp, downwards projection
What structures attach to the styloid process of the temporal bone?
Ones for the oral cavity & pharynx
Describe the petrous process of the temporal bone
A chunky, pyramid shaped, inwards projection
<p>What are the main features of the sphenoid bone</p>
<p>A body with two wings The body (including sella turcica) has a depression (the hypophysial fossa) for the pituitary gland The superior orbital fissure divides the wings into the lesser (anterosuperior) and greater (posterior) wings</p>
<p>What features of the ethmoid bone are visible from inside the cranium?</p>
<p>The cribiform plate, with lots of tiny holes The christa galli</p>
What is the only group of foramina in the anterior cranial fossa? And what posses through them?
The holes of the cribiform plate of the ethmoid bone containing the olfactory nerves
What’s the hypophysial fossa?
The depression in the body of the sphenoid bone where the pituitary sits
What are the 6 paired foramina in the middle cranial fossa?
Optic canal
Superior orbital fissure Foramen rotundum Foramen ovale Foramen spinosum (these 4 form that nice arch)
Foramen lacerum
What does the optic canal transmit?
Optic nerve
Opthalmic artery
What does the superior orbital fissure transmit?
Nerves for the extra-ocular muscles
V1 of trigeminal
Inferior opthalmic vein
What does the F. rotundum transmit?
Maxillary nerve
What does the F. ovale transmit?
Mandibular nerve
What does the F. spinosum transmit?
Middle meningeal artery
What does the F. lacerum transmit?
Nothing! It’s covered by a cartilage membrane in living people
What are the 4 foramina of the posterior cranial fossa?
Internal acoustic meatus
Jugular foramen
Hypoglossal canal
Foramen magnum
What does the int. acoustic meatus transmit?
Facial and vestibulocochlear nerves
What does the jugular foramen transmit?
Cranial nerves IX, X, XI
Internal jugular vein
(glossopharyngeal, vagus, accessory)
What does the hypoglossal canal transmit?
The hypoglossal nerve
Is the jugular foramen a foramen within a bone?
No - it’s a deficiency between the petrous process of the temporal bone and it’s joint with the occipital bone
From what aspect is the hypoglossal canal best seen?
From the inferior aspect, looking up
What are the 3 layers of the meninges?
Dura (outer)
Arachnoid (middle)
Pia (inner)
What part of the brain does the anterior cranial fossa house?
Frontal lobe
What part of the brain does the middle cranial fossa house?
Temporal lobe
What part of the brain does the posterior cranial fossa house?
Occipital lobe
Cerebellum
What bones form the anterior cranial fossa?
Horizontal plate of the fronal bone
Cribiform plate of ethmoid
Lesser wings of sphenoid
What bones form the middle cranial fossa?
Body in greater wings of sphenoid
Petrous part of temporal bone
What bones form the posterior cranial fossa?
Petrous part of temporal bone
Occipital bone
