Orbit Flashcards
what are the 6 bones that make up the Orbital osteology?
Frontal Ethmoid Shpenoid Zygomatic Lacrimal Maxillay
What two structure exit via the Optic canal?
CN 2
Ophthalmic artery
What exits the Superior Orbital Fissure?
CN3 CN$ CN5(V1) CN6 Superior Ophthalmic vein
What structures exit the Inferior Orbital Fissure?
CN5 (V2): infraorbital n. and zygomatic n.
Inferior Ophthalmic v.
Describe the relationships of the sinuses to the orbit?
Frontal sinus (most superior) Ethmoid sinus and Sphenoid Sinus (medial side) Maxillary Sinus (below the orbit)
A ______ fracture is a horizontal maxillary fracture separating the teeth from the upper face?
Le forte I
fracture line passes through the alveolar ridge, lateral nose and inferior wall of maxillary sinus
A _______ fracture is a pyramidal fracture with the teeth at the pyramid base, and nasofrontal suture at its apex?
Le Forte II
Fracture arch passes through posterior alveolar ridge, lateral wall of maxillary sinuses, inferior orbital rim and nasal bones.
A _______ fracture is a craniofacial disjunction.
Le Forte III
fracture line passes through nasofrontal suture, maxillo-frontal suture, orbital wall and zygomatic arch.
What are the three layers of the eye?
- outer protective
- middle: vascular
- Inner: sensory
______ and ______ are apart of the out protective layer of the eye?
sclera and cornea
Describe the middle vascular layer of the eye?
The choroid lays next to the cornea and swells turning into the ciliary body, which then extends into the iris.
What is the inner sensory layer comprised of?
Neural layer
pigmented layer
T/F the optic nerve retains all of the meningeal layer?
True
covered by meningeal dura, arachnoid membrane, and pia mater
Papilledema: increase in intracranial pressure will increase the pressure in the subarachnoid space, thus sqeezing the optic nerve
Describe the part of tear drainage?
Lacrimal gland Puncta Lacrimal canals Lacrimal sac Nasolacrimal duct Posterior nasal meatus
What happens if the puncta is blocked?
dry eyes and blurred vision
Describe the Parasympathetic innervation to the lacrimal gland?
Super Salivatory Nucleus send preganglionic fiber to the Sphenopalatine Ganglion (SPG) via the CNVIII, Greater superfical Petrosal N. and Vidian N.
Postganglionic fibers from the SPG innervate lacrimal gland travel via V2 and lacrimal N.
Describe the sympathetic innervation to the lacrimal gland.
Supplied by the Superior Cervical ganglion
gives rise to Deep petrosal n. and GSPN which fuse and become the Vidian N>
Post-ganglionic Fibers also travel through SPG but do not synapse
What are the layers of the eye?
- Skin
- Orbicularis Oculi
- Fat
- Orbital Septum: fascia
- levator Palpebrae Superioris
- Conjunctiva: continuation of sclera
What is the innervation, function and clinical sig. of Orbicularis Oculi m. (palpebral portion)?
innervation: CN VII
Function: close the eyelids and drain tears
Clinically: Bell’s palsy: facial paralysis
Corneal Reflex ( in w/ 5, out w/ 7)
______ and ______ are muscles of the eyelid?
Levator Palepbrae Superioris M (CN 3)
Tarsus Smooth m. (Muller’s): Innervated by sympathetics
What is the innervation, function and clinical sig. of levator Palpebrae Superioris m. ?
inserts into the palpebral fascia and skin of the upper lib
innervated by the GSE fibers to III n.
destruction of the III n. or one of its branches to this muscle results in paralysis of the LPS and complete ptosis
What is the innervation, function and clinical sig. of tarsal m.?
smooth muscle inserts on the tarsal plate of the upper lib Innervated: postganglionic sympathetic fibers
Horner’s syndrome: slight ptosis, miosis, and anhidrosis and flushing of the skin on the face may also be present
What are the 6 extraocular muscles?
Superior rectus Medial rectus Inferior rectus Lateral rectus Inferior Oblique Superior Oblique
The lateral Rectus is innervated by ______ and its function is ________.
CN 6
abduct eye
