Bones - Cranial Foramina Flashcards
What are all the cranial foramina?
From anterior to posterior:
1) Cribiform foramina
2) Inferior orbital fissure
3) Optic canal
4) Superior orbital fissure
5) Foramen rotundum
6) Foramen ovale
7) Foramen spinosum
8) Foramen lacerum
9) Internal acoustic meatus
10) Jugular foramen
11) Hypoglossal canal
Cribiform foramina
What bone are these foramina associated with?
Which cranial fossa is it located in?
What does it transmit?
Refers to the perforations of the cribiform plate of the ethmoid bone.
Connects the anterior cranial fossa with the nasal cavity.
The foramina allows passageway of axons of the olfactory nerve (CN I) from the olfactory epithelium of the nose into the cranial fossa where they communicate with the olfactory bulb.
Inferior orbital fissure
What does it transmit?
An opening in the maxillary bone.
Transmits the infraorbital artery, vein and nerve
Optic canal
Where is it located?
What does it transmit?
Bounded medially by the body of sphenoid and laterally by the lesser wing of sphenoid.
The opic canal permits passage of the optic nerve (CN II), ophthalmic artery and nerve.
Superior orbital fissure
Where is it located?
What areas does it connect?
Purpose?
What does it transmit?
Bounded superiorly by the lesser wing of sphenoid and inferiorly by the greater wing of sphenoid.
It enable communication between the apex of the bony orbit and the cavernous sinus.
It transmits several structures:
1) Frontal nerve (branch of the ophthalmic nerve)
2) Lacrimal nerve (branch of the opthalmic nerve)
3) Trochlear nerve (CN IV)
4) Oculomotor nerve (CN III)
5) Abducens nerve (CN VI)
6) Nasocilary nerve (a branch of the ophthalmic nerve)
7) Superior ophathalmic vein
8) A branch of the inferior ophthalmic vein
Foramen rotundum
Where is it located?
What areas does it connect?
What does it transmit?
Located inferior to the superior orbital fissure - at the base of the greater wing of sphenoid.
Provides a connection between the middle cranial fossa and the pterygopalatine fossa.
Transmits the maxillary nerve (CNV, V2).
Foramen ovale
Where is it located?
What does it transmit?
Another opening at the base of the greater wing of sphenoid, just posterolateral to the foramen rotundum.
It transmits the mandibular nerve (CNV, V3)
Foramen spinosum
Where is located?
What does it transmit?
Located laterally to the foramen ovale.
Transmits the middle meningeal artery and vein. It also transmits the meningeal branch of the mandibular nerve.
Foramen lacerum
Where is located?
What does it transmit?
Located posteromedial to the foramen ovale and anterior to the carotid canal.
It transmits a few structure:
Greater petrosal nerve - as it leaves it becomes the nerve of the pterygoid canal.
Small meningeal branches of the ascending pharyngeal artery.
Emissary veins from the cavernous sinus to the pterygoid venous plexus.
Internal acoustic meatus
Where is it located?
What areas does it connect?
What does it transmit?
Located in the petrous part of the temporal bone.
It connects the posterior cranial fossa to the inner ear.
It transmits the vestibulocochlear nerve (CN VIII) and the facial nerve (CN VII). It also transmits the labyrinthine artery and the vestibular ganglion.
Jugular foramen
Where is it located?
What does it transmit?
Formed anteriorly by the petrous part of the temporal bone and posteriorly by the occipital bone.
It can be divided into three compartments:
1) Anterior - contains the inferior petrosal sinus.
2) Middle - contains the glosspharyngeal nerve (CN IX), vagus nerve (CN X) and cranial part of the accesory nerve (CN XI).
3) Posterior - contains the sigmoid sinus and the meningeal branches of the occipital and ascending pharygeal arteries.
Hypoglossal canal
Where is it located?
What does it transmit?
Located in the occipital bone, near the foramen magnum.
It transmits the hypoglossal nerve (CN XII)
