ANAT 5010 - unit 13

calvaria

the upper dome of the neurocranium

frontal, ethmoid, sphenoid, temporal, occipital

what bones make up the cranial base?

squamous frontal bone to posterior edge of lesser wing of sphenoid

what are the borders of the anterior cranial fossa?

lesser wing of sphenoid bone to superior petrous ridges and dorsum sellae

what are the borders of the middle cranial fossa?

superior petrous ridges and dorsum sellae to the squamous occiput

what are the borders of the posterior cranial fossa?

zygomatic, sphenoid, frontal, lacrimal, ethmoid, palatine, and maxilla

what bones make up the orbit?

inferior orbital fissure and superior orbital fissure

which two openings allow structures to pass from the orbit into the middle cranial fossa?

dura mater

"tough mother"; outermost layer

arachnoid mater

thin, intermediate layer

pia mater

"delicate mother"; internal layer; one cell layer thick

periosteal (external) and meningeal (internal)

what are the two layers of the dura mater?

form partitions and gaps (dural venous sinuses)

what happens when the meningeal layer of the dura reflects away from the periosteal layer?

- falx cerebri

- falx cerebelli

- tentorium cerebelli

- diaphragma sella

what are the four partitions of dura mater?

falx cerebri

runs between the hemispheres of the cerebrum

falx cerebelli

runs between the hemispheres of the cerebellum

tentorium cerebelli

runs between the cerebrum and cerebellum

meningeal branches of CN V1, V2, and V3 to anterior and middle fossa

C2 and C3 spinal nerves innervation the dura of the posterior fossa

what innervates the dura?

arachnoid trabeculae and CSF

what is in the subarachnoid space?

enters arachnoid granulations that drain into the superior sagittal sinus that allows the CSF to return to the venous system

how does CSF drain in the brain?

epidural space

potential space between the periosteal dura and bones

bleed from the middle meningeal artery

what causes an epidural hematoma?

subdural space

potential space between the meningeal dura and arachnoid layer

venous bleed

what causes a subdural hematoma?

subarachnoid space

between arachnoid and pia mater; contains CSF and vessels

- internal carotid artery (anterior supply) - enters cranial cavity at carotid canal

- vertebral artery (posterior supply) - enters cranial cavity at foramen magnum

what are the main blood supplies to the brain?

- one anterior spinal artery

- two posterior spinal arteries

- posterior inferior cerebellar artery (PICA)

what are the branches of the vertebral artery?

- anterior inferior cerebellar artery (AICA)

- superior cerebellar artery

- posterior cerebral artery

what are the branches of the basilar artery?

- ophthalmic artery

- posterior communicating artery

- middle cerebral artery

- anterior cerebral artery

what are the branches of the internal carotid artery?

- posterior cerebral artery

- posterior communicating artery

- internal carotid artery

- anterior cerebral artery

- anterior communicating artery

what makes up the circle of willis (cerebral arterial circle)?

ophthalmic artery

runs in the optic canal; supplies most orbit structures

superior and inferior ophthalmic veins

what vessels facilitate primary orbit drainage?

- cavernous sinus (in superior orbital fissure)

- pterygoid plexus (in inferior orbital fissure)

where do the superior and inferior ophthalmic veins drain?

middle meningeal artery

passes through foramen spinosum to dura; forms meningeal grooves on the endocranial surface

middle meningeal vein

drains to pterygoid venous plexus in the deep face

receives: superior sagittal sinus, straight sinus, and occipital sinus

drains to: transverse sinus

what does the confluence of sinus receive and drain to?

receives: cerebral veins, arachnoid granulations

drains to: confluence of sinus

what does the superior sagittal sinus receive and drain to?

straight sinus

what does the inferior sagittal sinus drain to?

receives: inferior sagittal sinus and great cerebral vein

drains to: confluence of sinus

what does the straight sinus receive and drain to?

confluence of sinus

what does the occipital sinus drain to?

receives: cavernous sinus

drains to: transverse sinus

what does the superior petrosal sinus receive and drain to?

receives: cavernous sinus

drains to: sigmoid sinus

what does the inferior petrosal sinus receive and drain to?

receives: confluence of sinus and superior petrosal sinus

drains to: sigmoid sinus

what does the transverse sinus receive and drain to?

receives: transverse sinus and inferior petrosal sinuses

drains to: internal jugular vein

what does the sigmoid sinus receive and drain to?

receives: cerebral veins, ophthalmic veins, and sphenoparietal sinus

drains to: superior and inferior petrosal, basilar, and pterygoid venous plexuses

what does the cavernous sinus receive and drain to?

- ICA

- carotid sympathetic plexus

- CN |||

- CN |V

- CN V|

- CN V1

- CN V2

what are the contents of the cavernous sinus?

longitudinal fissure and falx cerebri

what separates the left and right cerebral hemispheres?

corpus callosum

what connects the left and right cerebral hemispheres?

- parietal

- temporal

- occipital

- frontal

what are the four lobes of the brain

cerebellum

"little brain"; occupies the posterior cranial fossa; processes coordination and fine movements

thalamus and hypothalamus

what makes up the diencephalon?

thalamus

sensory relay station

hypothalaus

autonomic relay station

CN ||| and CN |V

what does the midbrain give origin to?

origin: CN V, CN V|, CN V|||

receives: CN V||| (sensory)

what does the pons give origin to and receive?

posterior to the olive: CN |X, CN X, CN X|

anterior to the olive: CN X||

what does the medulla give origin to? (posterior and anterior to the olive)

- olfactory

- optic

- oculomotor

- trochlear

- trigeminal

- abducens

- facial

- vestibulocochlear

- glossopharyngeal

- vagus

- accessory

- hypoglossal

what are the cranial nerves in order?

Some Say Marry Money But My Brother Says Big Brains Matter More

what mnemonic differentiates the types of fibers in the cranial nerves?

CN | (olfactory)

axons project superiorly through the cribriform/olfactory foramina in the ethmoid bone

CN || (optic)

wrapped by meninges; runs in optic canal with ophthalmic artery

CN || (oculomotor), CN |V (trochlear), CN V| (abducens)

motor to extraocular muscles; emerge from brain stem, course through cavernous sinus, then the superior orbital fissure

CN |||: all extraocular muscles (besides superior oblique and lateral rectus) and preganglionic parasympathetic fibers that will synapse in the ciliary ganglion

CN |V: superior oblique muscle

CN V|: lateral rectus muscle

what are the targets of CN |||, CN |V, and CN V|?

CN V1 (ophthalmic)

exits the brain stem on the lateral pons; moves through cavernous sinus; enters orbit through the superior orbital fissure; SENSORY; branches into the nasociliary, frontal, and lacrimal

CN V2 (maxillary)

exits the brain stem on the lateral pons; moves through cavernous sinus; exits cranial cavity through the foramen rotundum; branches in the pterygopalatine fossa; sensory for meninges, maxillary sinus, nasal cavity mucosa, nasopharyngeal mucosa, palate, upper teeth, and skin of the midface

CN V3 (mandibular)

exits the brain stem on the lateral pons; moves directly through foramen ovale; motor to muscles of mastication, anterior digastric, mylohyoid, TVP, and TTymp; sensory from meninges, skin of lower face and parotid region, TMJ and ear canal, lower teeth, and anterior 2/3 of tongue (not taste)

CN V|| (facial)

exits the brain stem at the pontomedullary junction; exits cranial cavity at the internal auditory meatus; motor to muscles of facial expression, posterior digastric, stylohyoid, and stapedius; parasymp motor to lacrimal, nasal, sublingual, and submandibular glands; special sensory for taste for anterior 2/3 of tongue (chorda tympani)

CN V||| (vestibulocochlear)

exits the brain stem at the pontomedullary junction; exits cranial cavity at the internal auditory meatus; sensory only; vestibulo = balance, cochlear = hearing

CN |X (glossopharyngeal)

exits the brain stem at the postolivary sulcus in the medulla; exits cranial cavity at the jugular foramen; motor to stylopharyngeus; parasymp motor to parotid gland; special sensory for taste from the posterior 1/3 of tongue

CN X (vagus)

exits the brain stem at the postolivary sulcus in the medulla; exits cranial cavity at the jugular foramen; motor to muscles of the palate; parasymp motor to glands of larynx, heart, lungs, GI tract to mid transverse colon; sensory in larynx, lungs, heart, esophagus, GI tract to mid transverse colon; special sensory for taste from the epiglottic region

CN X| (accessory)

exits the brain stem at the postolivary sulcus in the medulla; exits cranial cavity at the jugular foramen; motor to trapezius and SCM

CN X|| (hypoglossal)

exits the brain stem at the preolivary sulcus in the medulla; exits cranial cavity at the hypoglossal foramen; motor to tongue

orbital septum

extension of periosteum; attachment for tarsal plates and levator palpebrae superioris muscle

tarsal plates

plates of dense connective tissue in the eyelids

conjunctiva

lines sclera and inside eyelid

lacrimal lake

pool of fluid in medial canthus

lacrimal caruncle

pink fleshy bump near medial canthus

lacrimal papilla

elevation on medial eyelid; have tiny holes called punctum

lacrimal puncta

tiny holes on each papilla that drain into the canaliculi then to nasolacrimal sac, duct, and finally into inferior nasal meatus

facial nerve (and some sympathetic fibers)

innervates the lacrimal gland

- ophthalmic artery from ICA

- infraorbital artery (from maxillary) and angular artery (from facial) from the ECA

what vessels supply the eyelids?

CN V1

sensory innervation for upper eyelid

CN V2

sensory innervation for lower eyelid

- superior rectus

- inferior rectus

- medial rectus

- lateral rectus

what are the recti muscles of the eye?

- superior oblique

- inferior oblique

what are the oblique muscles of the eye?

levator palpebrae superioris

what is the eyelid muscle?

nerve: CN ||| and sympathetic

testing position: raise eyelid

what is the nerve and testing position of the levator palpebrae superioris?

nerve: CN IV

testing position: adduct, depress

what is the nerve and testing position of the superior oblique?

nerve: CN III (inferior branches)

testing position: adduct, elevate

what is the nerve and testing position of the inferior oblique?

nerve: CN III (superior branches)

testing position: abduct, elevate

what is the nerve and testing position of the superior rectus?

nerve: CN III (inferior branches)

testing position: abduct, depress

what is the nerve and testing position of the inferior rectus?

nerve: CN III (Inferior branches)

testing position: adduct

what is the nerve and testing position of the medial rectus?

nerve: CN VI

testing position: abduct

what is the nerve and testing position of the lateral rectus?