Skull Foramina PDF

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SKULL FORAMINA WEEKS 1-3...

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1. Name all those holes in the base of the skull and tell us what goes through each. Cranial fossa

Bone

Foramina

Vessels

Nerves

supraorbital foramen

supraorbital artery, supraorbital nerve supraorbital vein

frontal

anterior cranial fossa

foramen cecum

emissary veins to superior sagittal sinus

-

ethmoid

-

foramina of cribriform plate

-

olfactory nerve bundles (I)

ethmoid

anterior cranial fossa

anterior ethmoidal foramen

ethmoid

anterior cranial fossa

posterior ethmoidal foramen

sphenoid

-

optic canal

frontal

-

anterior ethmoidal artery anterior ethmoidal vein posterior ethmoidal artery posterior ethmoidal vein ophthalmic artery

anterior ethmoidal nerve

posterior ethmoidal nerve optic nerve (II) oculomotor nerve (III) trochlear nerve (IV) lacrimal, frontal and nasociliary branches of ophthalmic nerve (V 1 ) abducent nerve (VI)

sphenoid

middle cranial fossa

superior orbital fissure

superior ophthalmic vein inferior ophthalmic vein

sphenoid

middle cranial fossa

foramen rotundum

-

maxillary nerve (V 2 )

-

incisive foramen/incisive canals

sphenopalatine artery

nasopalatine nerve(V2)

-

greater palatine foramen

-

lesser palatine foramina

-

inferior orbital fissure

maxilla

palatine palatine and maxilla sphenoid and maxilla

greater palatine artery greater palatine vein lesser palatine artery lesser palatine vein inferior ophthalmic veins infraorbital artery

greater palatine nerve

lesser palatine nerve zygomatic nerve and infraorbital nerve of maxillary nerve (V 2 )

infraorbital vein

orbital branches of pterygopalatine ganglion

maxilla

-

infraorbital foramen

infraorbital artery infraorbital vein

infraorbital nerve

sphenoid

middle cranial fossa

foramen ovale

accessory meningeal artery

mandibular nerve (V 3 ) lesser petrosal nerve (occasionally)

sphenoid

middle cranial fossa

foramen spinosum

middle meningeal artery

meningeal branch of the mandibular nerve (V 3 )

sphenoid

temporal

middle cranial fossa middle cranial fossa

internal carotid foramen lacerum artery, artery of pterygoid canal

nerve of pterygoid canal

internal acoustic meatus

labyrinthine artery

facial nerve (VII), vestibulocochlear nerve (VIII)

inferior petrosal sinus, sigmoid sinus

glossopharyngeal nerve (IX), vagus nerve (X), accessory nerve (XI)

temporal

posterior cranial fossa

jugular foramen

occipital

posterior cranial fossa

hypoglossal canal -

hypoglossal nerve (XII)

occipital

posterior cranial fossa

anterior and posterior spinal foramen magnum arteries, vertebral arteries

medulla oblongata

temporal

posterior cranial fossa

stylomastoid foramen

stylomastoid artery facial nerve

2. Review the boundaries of anterior, middle and posterior cranial fossa. Anterior cranial fossa: Anterior limit is the posterior wall of the frontal sinus. The anterior clinoid processes and the planum sphenoidale, which forms the roof of the sphenoid sinus, mark the posterior limit. The frontal bone forms the lateral boundaries. The frontal bone houses the supraorbital foramina, which, along with the frontal sinuses, form 2 important surgical landmarks during approaches involving the anterior skull base. Middle cranial fossa: The greater wing of the sphenoid helps form the anterior limit of the middle skull base. The posterior limit is the clivus. The greater wing of the sphenoid forms the lateral limit as it extends laterally and upward from the sphenoid body to meet the squamous portion of the temporal bone and the anteroinferior portion of the parietal bone. The greater wing of the sphenoid forms the anterior floor of the fossa. The anterior aspect of the petrous temporal bone forms the posterior floor of the middle cranial fossa. The body of the sphenoid makes up the central portion of the middle fossa and houses the sella turcica. Posterior cranial fossa: The posterior skull base consists of primarily the occipital bone, with contributions from the sphenoid and temporal bones. The basal portion of the occipital bone (the basiocciput) and the basisphenoid form the anterior portion of the

posterior skull base. These 2 regions combine to form the midline clivus. The posterior surface of the petrous temporal bone and the lateral aspect of the occipital bone form the lateral wall. The occipital bone also fuses with the mastoid portion of the temporal bone to form the occipitomastoid suture. The petrous portion of the temporal bone and the greater wings of the sphenoid bone are particularly important for identifying structures. The overlying tentorium cerebelli separates the cerebellum from the cerebral hemispheres above, whereas the occipital bone form the lateral walls and floor. 3. List the contents of the superior and inferior orbital fissures. Superior orbital fissure:      

superior and inferior divisions of oculomotor nerve (III) trochlear nerve (IV) lacrimal, frontal and nasociliary branches of ophthalmic nerve (V1 ) abducens nerve (VI) superior and inferior divisions of ophthalmic vein. Inferior division also passes through the inferior orbital fissure. sympathetic fibers from cavernous plexus

The nerves passing through the fissure can be remembered with the mnemonic, "Live Frankly To See Absolutely No Insult" - for Lacrimal, Frontal, Trochlear, Superior Division of Oculomotor, Abducens, Nasociliary and Inferior Division of Oculomotor nerve. It is divided into 3 parts from lateral to medial: Lateral Part transmits: lacrimal nerve, frontal nerve, trochlear nerve, meningeal branch of lacrimal artery, anastomotic branch of middle meningeal artery which anastomoses with recurrent branch of the lacrimal artery Middle Part transmits: Upper and lower divisions of the oculomotor nerve, nasociliary nerve between the two divisions of oculomotor nerve and abducent nerve Medial Part transmits: Superior ophthalmic vein and sympathetic nerves from the plexus around internal carotid artery Inferior orbital fissure: infraorbital nerve (a branch of V2), infraorbital artery (a branch of the third part of the maxillary artery) Anatomy of the left orbital apex, highlighting the extraocular muscle origins and the contents of the superior orbital fissure. Key: LPS, levator muscle; SR, superior rectus; LR, lateral rectus; IR, inferior rectus; MR, medial rectus; SO, superior oblique; SOV, superior ophthalmic vein; III sup , superior division of oculomotor nerve; III inf , inferior division of oculomotor nerve; IOF, inferior orbital fissure....