Orbit and Extraocular Muscle Testing Pt. 2 Flashcards
What are the 5 structures in the orbit that receive autonomic innervation?
- ) Dilator pupillae muscle
- ) Constrictor pupillae muscle
- ) Ciliary Muscle
- ) Levator palpebrae (smooth muscle part)
- ) Lacrimal gland
Of these 5, which two only get SYMPATHETIC innervation?
Dilator pupillae and levator palpebrae
Of these 5, which two receive only PARASYMPATHETIC innervation?
constrictor pupillae and ciliary
OF these 5, which is the only one to receive BOTH sympathetic and parasympathetic innervation
Lacrimal gland
The sympathetic innervation of the dilator pupillae and levator palpebrae is via postganglionic fibers whose cell bodies are in the
Superior cervical ganglion
The preganglionic sympathetic fibers arrise from
T1
The parasympathetic innervation to the lacrimal gland is via the
Greater petrosal branch of CN VII (preganglionic) and the pterygopalatine ganglion (post ganglionic)
The parasympathetic innervation to the constrictor pupillae and ciliary muscles is via
CN III (preganglionic) and ciliary ganglion (post ganglionic)
The ciliary ganglion contains cell bodies of
Post ganglionic parasympathetic neurons
Preganglionic parasympathetic axons from CN III enter the ciliary ganglion through the
Motor root
The post ganglionic axons then leave the ciliary ganglion through the short ciliary nerves and to the eyeball to innervate the
Sphincter pupillae and cilliary muscles
Contains sensory fibers from CN V1 and postganglionic sumpathetic axons from cell bodies in the superior cervical ganglion that pass through wihtout synapsing
Ciliary ganglion
What is the sensory nerve in the orbit for special sensation?
Optic nerve (II)
What is the sensory nerve in the orbit for general sensation?
Opthalmic (V1) and maxillary (V2) divisions of the trigeminal nerve
The eyeball receives general sensory innervation from the
Long ciliary and short ciliary nerves, which are branches of the nasociliary nerve (branch of V1)
Pass through the ciliary ganglion on their way to the eyeball
Sensory fibers in short ciliary nerve
What are the other sensory nerves that pass through the orbit to provide general sensory innervation to the face, paranasal sinuses, and cranial cavity?
Frontal nerve, lacrimal nerve, infraorbital nerve, and zygomaticotemporal and zygomaticofacial nerves
All of the sensory fibers of the trigeminal nerve have their cell bodies in the trigeminal ganglion located in the
Middle cranial fossa
Prior to entering the orbit, CN V1 divides into the
Lacrimal, frontal, and nasociliary nerves
Within the orbit, the frontal nerve divides into the
Supraorbital and supratrochlear nerves
Gives rise to the Sensory root of the ciliary ganglion, the long ciliary nerve, the ethmoidal nerves, and the infratrochlear nerve
Nasociliary Nerve
Provides sensation from the eyeball
Sensory root of ciliary ganglion and long ciliary nerve
PRovides sensation from the ethmoid air cells, the anterior cranial fossa, and the nasal cavity
Ethmoidal nerves
Provides sensation from the face
Infratrochlear nerce
Prior to entering the orbit, CN III divides into a
Superior and inferior division
The superior division of CN III carries SOMATIC motor innervation to the
Levator palpebrae superioris and superior rectus
The inferior division of CN III carries somatic motor innervation to the
Inferior and medial rectus and the inferior oblique
The inferior division of CN III also carries preganglionic parasympathetic innervation to the
Ciliary ganglion
CN IV and CN VI enter the orbit and each innervate one muscle, which are they?
CN IV = superior oblique
CN VI = lateral rectus
A branch of the internal carotid artery that enters the orbit through the optic canal along with the optic nerve
Opthalmic artery
Sole blood supply to the visual receptor cells of the retina
-Branch of opthalmic artery
Central artery of the retina
Communicates with several veins of the face, receives tributaries within the orbit, and then exits the orbit through the superior orbital fissure to enter the cavernous sinus
Superior opthalmic vein
Receives tributaries within the orbit and then divides into two branches
Inferior opthalmic vein
One branch exits the orbit through the inferior orbital fissure to drain into the
Pterygoid plexus in the infratemporal fossa
The other branch drains into the
Superior opthalmic vein
Usually the pressure gradient of the opthalmic veins is such that blood flow is from
Within the cranial cavity outward
Can travel to the cavernous sinus and may lead to septic cavernous sinus thrombosis (potentially fatal)
Superficial cutaneous infection of the face
Which structures passTHROUGH the common ring tendon of the four rectus muscles?
- ) CN II
- ) CN III (sup. & inf.)
- ) CN VI
- ) Nasociliary nerve of V1
- ) Opthalmic artery
What are the structures that pass OUTSIDE of the ring tendon?
- ) CN IV
- ) Frontal and lacrimal nerves of V1
- ) Infraorbital and zygomatic nerves of V2
- ) Opthalmic veins