Foramina, fissures, and fossa Flashcards
Foramen (pl: foramina)
Hole or opening in bone
- allows the entrance and exit of nerves/vessels in and out of the orbit.
- Optic foramen/canal, supraorbital foramen (hole in frontal bone), supratrochlear foramen, infraorbital foramen (hole in maxillary bone)
Fissure
Long, narrow opening in bone
Allows entrance and exit of nerves and vessels in and out of the orbit
Superior orbital fissure, inferior orbital fissure (in maxillary bone on floor)
Fossa
Shallow depression in bone.
Anatomical structures are positioned in fossa.
Lacrimal fossax2
Foramen that lies between the lesser wing and body of the sphenoid
Optic foramen (optic canal)
Where is the optic canal/foramen located
Lies between the lesser wing and body of sphenoid
At the orbital apex (posterior), slightly nasal
Opening between the orbit and cranial cavity.
Tendinous ring or annulus of zinn
Lies anterior to the optic canal. Lies anterior to the INFERIOR part of the supraorbital fissure. Band of connective tissue that is the origin for four of the extra ocular muscles.
What passes through the optic canal and annulus of zinn
CN 2 and the ophthalmic ARTERY
Where does the superior orbital fissure (supraorbital fissure) lie
Lies between the greater and lesser wings of the sphenoid. It is in the inferior part of the the apex (slightly nasal and posterior).
Nerves that pass through the inferior part of the superior orbital fissure and THROUGH the annulus of Zinn
Superior and inferior division of the oculomotor nerve (CN III), nasociliary nerve (CN V1) and the abducens nerve (CNV1)
Superior to inferior- S.A.N.I S uperior branch of oculomotor nerve III A bducens nerve (VI AKA 6) N asociliary nerve (CN V1) I inferior branch of oculomotor nerve III
Three divisions of the trigeminal (CN V AKA 5) nerve
V1- Ophthalmic - Frontal nerve (supraorbital and supratrochlear nerves that exit through the supraorbital notch/foramen and supratrochlear notch/foramen) -Lacrimal nerve -Nasociliary nerve V2- Maxillary - Zygomatic nerve - Infraorbital nerve, artery, and vein V3- Mandibular
Nerves and vessels that pass through the superior orbital fissure and ABOVE the annulus of zinn.
(Superior to inferior)
Lacrimal Nerve (CN V1) Frontal nerve (CN V1) Trochlear nerve (CN IV AKA 4) Superior ophthalmic VEIN
common tendinous ring is __ to the optic canal and ___ to the superior orbital fissure
Anterior to the optic canal and anterior to the inferior portion of the superior orbital fissure.
__
C
With
Where is the inferior orbital fissure (infraorbital fissure) located and what passes through it
Lies between the floor of the orbit and the lateral wall. Inferior to the tendinous ring. Nerves and vessels pass through including the:
Inferior ophthalmic VEIN Zygomatic nerve (CN V2) Infraorbital nerve (CN V2) artery and vein.
V2= apart of the maxillary division of the trigeminal nerve (nerve #5)
Where do nerves and vessels pass through after exiting the infraorbital fissure
Continue through the infraorbital groove/canal and out the infraorbital foramen
Lacrimal fossa
Depends on what lacrimal structure you are looking for. There are 2 lacrimal fossa.
1 located in the temporal portion of the frontal bone. Holds the lacrimal GLAND.
The other is located medially, separated from the orbit by the orbital septum (anterior and medial to the orbit) an is where the lacrimal sac sits.
Where does the lacrimal gland sit
In the lacrimal fossa, which is located in in the temporal portion of the frontal bone.
Where does the lacrimal sac sit
The lacrimal sac sits in the lacrimal fossa that is located medially and anterior to the orbit. This lacrimal fossa and the lacrimal sac are technically not apart of the orbit. This prevents infection from the sac from spreading to the orbit.
How does the lacrimal fossa/sac extend into the nasal cavity
The nasolacrimal canal (which holds the nasolacrimal duct) is in the maxillary bone and extends from the fossa to open in the nasal cavity
Which bones form the posterior and anterior lacrimal crests of the lacrimal fossa
The lacrimal bone forms the posterior crest and the frontal process of the maxillary bone forms the anterior crest. This is where the lacrimal sac will sit, outside of the orbit
How is the lacrimal sac and fossa separated from the orbit
It is separated medially and anteriorly by the orbital septum, which is a sheet of dense connective tissue. Prevents disease from spreading.
Another word for sulcus
Fossa
Another word for fossa
Sulcus
What are the 2 foramens/notches located superior to the orbit
Supraorbital foramen/notch and more medially, the supratrochlear foramen/notch. Both are openings between the orbit and facial surface.
What passes through the supraorbital foramen/notch
Supraorbital nerve (CN V1), artery and vein pass through
This nerve is apart of the ophthalmic division and considered a frontal nerve.
What passes through the supratrochlear foramen/notch
Supratrochlear nerve (CN V1) artery and vein pass through.
This nerve is apart of the ophthalmic division and considered a frontal nerve.
What passes through the infraorbital foramen
Infraorbital nerve (CN V2) artery and vein. Pass through the inferior orbital fissure, then down the infraorbital groove and out through the infraorbital foramen.
