8 Cranial Nerves Of Eye And Orbit Flashcards
List the cranial nerves associated with the eye, orbit, and associated structures (7).
(CNs 2-7, minus V3)
CN II: optic nerve CN III: oculomotor CN IV: trochlear CN V: trigeminal (ophthalmic and maxillary divisions) CN VI: abducens nerve CN VII: facial nerve
Describe the location and path of each cranial nerve, starting from the cavernous sinus area and ending at its terminal branches:
Trigeminal Nerve, V1.1
(ophth div: nasociliary nerve)
The nasociliary runs along medial aspect of the orbit. After splitting off branches to the 2 long ciliary nerves and the sensory root to the ciliary ganglion, it continues traveling medially and gives rise to 2 more medial branches: posterior ethmoidal nerve and, soon-after, the anterior ethmoidal nerve. It continues along to become the infratrochlear nerve as it exits the orbit below the trochlea to penetrate the orbital septum and receives sensory fibers to the surrounding area of the medial canthal: caruncle, canaliculi, lacrimal sac, medial aspect of the eyelids, and skin at the side of the nose.
What are the branches of V1?
V1 leaves Trigeminal ganglion and goes through the cavernous sinus. It soon splits into three branches:
- Lacrimal Nerve
- Frontal Nerve
- Nasociliary Nerve
Describe the location and path of each cranial nerve, starting from the cavernous sinus area and ending at its terminal branches:
Trigeminal Nerve, V1.2
(ophth div: Frontal Nerve)
- Enters the orbit through the superior orbital fissure above the common tendinous ring.
- The Frontal Nerve splits into the Supraorbital nerve and Supratrochlear nerve midway through the orbit.
- Supratrochlear receives fibers of skin and muscles of the forehead and upper eyelid.
- Supraorbital nerve (accompanied by s/o artery) exits through the supraorbital notch and receives from (more laterally) the skin and muscles of the forehead and upper eyelid.
Describe the location and path of each cranial nerve, starting from the cavernous sinus area and ending at its terminal branches:
Trigeminal Nerve, V1.3
(Ophth Div: Lacrimal Nerve)
- Branches off in lateral fashion to the Frontal Nerve (V-1.2).
- Enters orbit via Suprior Orbital Fissure, above the muscle cone.
- Splits into a branch containing the autonomic innervation of the lacrimal glad, the zygomatic nerve.
- Terminates at sensory fibers from the lacrimal gland and lateral aspect of the upper eyelid and temple area.
discuss the components of each cranial nerve discussed: motor, sensory, autonomic
list and describe the fxn of each cranial nerve discussed
…
The ophthalmic nerve (V-1) exits the ____ wall of the cavernous sinus (with respect to a posterior-to-anterior direction).
lateral
Describe the location and path of each cranial nerve, starting from the cavernous sinus area and ending at its terminal branches:
Trigeminal Nerve, V-2.1
(Max div: Infraorbital Nerve)
(-V2 splits into two branches: infraorbital nerve and zygomatic nerve.)
- Infraorbital Nerve, the more medial of the two, enters orbit through the inferior orbital fissure.
- While in the Maxillary bone, gives off branches to upper teeth and maxillary sinus.
- Exits Maxillary bone through the infraorbital foramen.
- Receives sensory fibers from cheek, upper lip, lower eyelid.
Describe the location and path of each cranial nerve, starting from the cavernous sinus area and ending at its terminal branches:
Trigeminal Nerve, V-2.2
(Max div: Zygomatic Nerve)
…
- Zygomatic Nerve exits Zygomatic bone as:
1. zygomaticofacial nerve, goes to receive sensory fibers from the lateral aspect of the cheek and lower eyelid
2. zygomaticotemporal nerve, goes to receive sensory fibers from the lateral aspect of the forehead (also has communicating branch to the lacrimal nerve of V-1)
The lacrimal nerve leaves the lacrimal gland and runs _____ along the upper border of the _________ muscle.
posteriorly
lateral rectus
The lacrimal nerve exits the orbit through the __________ and ______ the muscle cone.
superior orbital fissure
above
With respect to a posterior to inferior direction, the infraorbital nerve exits the maxillary bone through the __________.
infraorbital foramen
The _______ nerve passes near the pterygopalatine fossa and receives some autonomic fibers from the pterygopalatine ganglion.
maxillary
The cranial nerves that supply the motor functions of the orbit and adnexa are:
CN III (oculomotor) CN IV (trochlear) CN VI (abducens) CN VII (facial)
these motor nerves are the e-fferent pathway
The ________ nerve pierces the roof of the cavernous sinus and runs within the two dural layers of the lateral wall, above the trochlear nerve.
oculomotor
While in the cavernous sinus, the oculomotor nerve sends small sensory branches to the _______ nerve and receives sympathetic fibers from the _________.
ophthalmic
plexus around the internal carotid artery
CN III enters the orbit through the ________.
CN III divides into _____ and _____ divisions, but both divisions are still located within the _______ foramen.
superior orbital fissure
superior, inferior
oculomotor
The superior branch of the ______ runs medially above the optic nerve and enters the superior rectus on its _____ surface.
Additional fibers pierce either the muscle or pass around its border to innervate the _______.
oculomotor nerve (CN III)
inferior
levator palpebrae superioris
The inferior branch of the _______ runs below the _____ and divides into 3 branches:
- One enters the medial rectus on its ______.
- One enters the inferior rectus on its ______.
- One gives off _______ fibers that form the ________ extending to the ciliary ganglion.
oculomotor nerve (CN III)
- lateral side
- upper surface
- parasympathetic, parasympathetic root
The _____ nerve is a motor-only nerve that innervates the superior oblique muscle.
This nerve enters the wall of the cavernous sinus and lies between the ______ and the ________(of ___).
While in the cavernous sinus, it sends sensory fibers to ______.
trochlear (think SO4)
oculomotor nerve (CN III) ophthalmic division of the trigeminal nerve (CN V)
the ophthalmic nerve
The trochlear nerve, CN IV, enters the orbit through the __________ fissure at a point (above/below) the common tendinous ring and (inside/outside) the muscle cone.
CN IV runs alongside the ______ to the medial side of the orbit above the _______ (2 muscles) and enter the upper surface of the ________ muscle, where it innervates.
superior orbital
above
outside
frontal nerve (of V-1)
levator muscle and superior rectus muscle
superior oblique
- Within the cavernous sinus, the abducens, CN VI, is tucked right up against this non-nerved structure and it’s small sympathetic branches (from it’s plexus) leave to travel alongside the abducens.
- The abducens carries these autonomic fibers and sensory fibers to the ___________ division of the trigeminal nerve.
- (the lateral wall of) the internal carotid
2. ophthalmic division
CN VI enters the orbit through the _______ and (inside/outside) of the common tendinous ring.
The abducens innervates the _________ muscle on the ______ surface.
superior orbital fissure
inside
lateral rectus (LR6) medial
- The motor fibers of the facial emerge through the ________ and then pass below the __________ canal, travel over the ________ ramus, and divide into several branches.
- What are the upper two branches?
- What do they supply?
1. stylomastoid foramen external auditory canal mandibular ramus 2. temporal branch, zygomatic branch 3. the frontalis, procerus, corrugator, and orbicularis muscles.
