Anatomy W5 - Cranial Cavity part 2 Flashcards
What is the vault of the skull rich in?
Red bone marrow
What is the boundary between the anterior cranial fossa and the middle cranial fossa?
The lesser wing of the sphenoid bone
What structure does the pituitary reside in (middle cranial fossa) ?
Sella tursica /The hypophyseal fossa
What is the boundary between the middle cranial fossa and the posterior cranial fossa?
The superior border of the petrous part of the temporal bone and the dorsum sellae
On what part of the sphenoid bone does the brainstem lie?
The clivus
What is the foramen lacera?
A hole in the floor of the cranial cavity where a cartilage precursor persists unossified.
What veins drain into the superior sagittal sinus?
The superior cerebral veins
In what direction does blood flow in the dural venous sinuses?
From front to back
What does the vein of Galen/the great cerebral vein drain?
The midline of the forebrain (thalamus and the hypothalamus)
What growth plate is present near the clivus on the floor of the cranial cavity?
The spheno-occipital growth plate
When does The spheno-occipital growth plate start to fuse?
12 years and onwards (until age of 25)
Where is the foramen magnum located?
On the baslar part of the occipital bone
Where are nerves that supply muscles formed from pharyngeal arches situated in relation to the midline of the brain?
Further from the midline
Where are nerves that supply muscles formed from somites situated in relation to the midline of the brain?
Closer to the midline
What Cranial nerves comes off the brainstem as rootlets (instead of bundles)?
CN 9, 10, 11 & 12
Rootlets of what cranial nerve(s) come from the RETRO olivary sulcus in the in the medulla oblongata of the brainstem?
CN 9, 10 & 11
Rootlets of what cranial nerve(s) come from the PRE olivary sulcus in the medulla oblongata of the brainstem?
CN 12
What are the signs of damage to the Oculomotor nerve CN 3?
Levator palpebrae superioris not being innervated = Eye lid droops/cant open
Eye drifts to the side since the medial rectus is not pulling the eye towards the centre (adducts).
How can you assess if the pupils are symmetrical?
Look for the highlight on the pupils - are they in the same place?
Look at the amount of sclera on each side of the pupil - is it the same?
What muscle is used in the light reflex?
What is the nerve supply to this muscle?
The constrictor papillae muscle.
Parasympathetic fibres from the oculomotor nerve.
What nerve supplies the angle of the mandible?
The C2 & C3 spinal nerves - not a cranial nerve
Define dermatome.
An area of skin supplied by any particular cranial or spinal nerve
When is facial paralysis given the name Bells Palsy?
When the cause is unknown
What is the risk of a patient getting a schwannoma of CN 8 removed?
Since CN 7&8 run close together through the internal acoustic meatus there is a risk that there could be damage to the facial nerve = facial palsy that affects the whole side of her face.
What nerve innervates the larynx?
The vagus
What is Horner’s syndrome?
Damage to the sympathetic NS
What can cause Horner’s syndrome?
Congenital defects
Malignancy
Stroke
Trauma to neck
What are the symptoms of Horner’s syndrome?
Constriction of the pupil on that side - dilator is under sympathetic control.
Lack of sweat on that side - controlled by sympathetic NS
Drooping eyelid (ptosis) - mix of skeletal muscle from CN 3 and smooth muscle - smooth muscle is under sympathetic control.
Where is the superior cervical ganglion located?
Behind the bifurcation of the carotid artery
What structures in the ventricles of the brain produce CSF?
Choroid plexus
Describe the constant turn over of CSF.
Choroid plexus in the ventricles produce CSF, CSF fills the subarachnoid space.
The arachnoid villi extend from the subarachnoid space into the superior sagittal sinus and allow CSF to enter into the venous circulation.
What do you call the large collection of CSF near the brainstem?
The systerna magna
