Dissection 14 Flashcards
What bones make up the ocular orbit?
Where are the sinuses that line the orbits?
Name and locate the foramina of the orbit
Name and locate the bones that make up the medial wall of the orbit
Name the four layers of fascia in the orbit
- Periorbita
- Fascia of extraocular muscles
- Bulbar fascia
- Optic nerve sheath
Periorbita fascia
Lines the bony orbit
Continuous with periosteal dura in the skull
Fuses with optic nerve sheath at optic canal
Optic Nerve Sheath
- Continuous with meningeal dura
- Encloses arachnoid and pia mater
Two types of conjunctiva
- Bulbar on the eye
- Palpebral on the inside of the eyelid
Three muscles of the eyelids
- Levator Palpebrae Superioris
- Skeletal
- Opens eye
- CN III
- Superior Tarsal Muscle
- Smooth
- Opens eye
- Sympathetics that run with CN III
- Orbicularis Oculi
- Closes eye and spreads tears
- CN VII
Where is the lacrimal gland?
Superior lateral orbit
Pathway for tears
- Drains into lacrimal puncta
- Lacrimal sac in lacrimal groove
- Nasolacrimal duct to nasal cavity
- Out of nose
What muscle changes the shape of the lens?
Ciliary muscle; under parasympathetic control
What dilates the pupil?
Pupillary Dilator; radial fibers; sympathetic control
What constricts the pupil?
Pupillary Sphincter; Circular fibers; parasympathetic control
What muscles do NOT attach to the common tendinous ring?
Levator Palpebrae Superioris
Superior Oblique
Both attach above the ring
Name and locate the extraocular muscles (picture)
What eye muscles only act around the vertical axis?
Medial Rectus- adduction
Lateral Rectus- Abduction
What muscles act around all three axes?
- Superior Rectus
- Elevates, adducts, medially rotates
- Inferior Rectus
- Depresses, Adducts
- Laterally rotates
- Superior Oblique
- Depresses, abducts, medially rotates
- Inferior Oblique
- elevates, abducts, laterally rotates
What muscles serve to adduct the eye?
- Medial Rectus
- Superior Rectus
- Inferior Rectus
What muscles abduct the eye?
- Lateral rectus
- Superior Oblique
- Inferior Oblique
What muscles elevate the eye?
- Superior rectus
- Inferior Oblique
What muscles depress the eye?
- Inferior rectus
- Superior Oblique
What muscles are involved with eyeball intorsion?
Superior Rectus
Superior Oblique
What muscles are involved with extorsion?
Inferior Rectus
Inferior Oblique
Name the cranial nerves that send innervation to the orbit
III, IV, V1, VI, VII, sympathetics
What innervates the orbicularis oculi?
CN VII
Branches of V1 in the orbit from medial to lateral
- Nasociliary Nerve
- Frontal Nerve
- Lacrimal Nerve
Come from trigeminal ganglion; Lacrimal and Frontal split
Most superficial layer of fascia in the orbit
Periorbita fascia
What does the frontal nerve split into after the lacrimal nerve splits off?
Supratrochlear nerve
Supraorbital nerve
Difference between short and long ciliary nerves
Short nerves go from the ciliary ganglion to the eye while long nerves go straight from the nasociliary nerve to the eye
Parasympathetic nerve targets in the orbit
Pupillary sphincter
Ciliary muscle
Lacrimal gland
Travel with branches of trigeminal nerve
Targets of sympathetic nerves in the orbit
- Pupillary dilator
- Superior tarsal muscle
- Lacrimal gland
- Travel with blood vessels and cranial nerves
How do parasympathetic fibers get from the pterygopalatine ganglion to the lacrimal gland?
Zygomatic branch of V2 to communicating branch to V1 to lacrimal gland
How do sympathetic fibers get to the pupillary dilator?
- Lateral horn of spinal cord (presynaptic cell body)
- Superior cervical ganglion (postsynaptic)
- Carotid plexus
- Ciliary Ganglion
How do sympathetic fibers get to the superior tarsal muscle?
- Lateral horn of spinal cord (presynaptic cell body)
- Superior cervical ganglion (postsynaptic)
- Carotid Plexus
- Superior branch of III
How do sympathetic fibers get to the lacrimal gland?
- Lateral horn
- Superior cervical ganglion
- Carotid plexus
- Deep petrosal nerve
- Pterygopalatine ganglion
- V2
- Lacrimal gland
What do short ciliary nerves carry that long ciliary nerves don’t?
Parasympathetics
Both carry sympathetics and somatosensory
What main artery carries blood to the orbits?
Ophthalmic Artery
Branches of ophthalmic artery that leave the orbit
- Ethmoidal Artery
- Supratrochlear Artery
- Dorsal Nasal Artery
- Supraorbital Artery
Branches of ophthalmic artery that stay in the orbit
- Central artery of retina
- Posterior ciliary arteries
- Lacrimal arteries
- Muscular arteries
What does the ophthalmic artery anastomose with?
Middle Meningeal Artery
Branches of Facial Artery
How does the cornea get oxygen?
Diffusion only; that area is avascular!!!
What veins drain blood from the eye?
- Superior ophthalmic vein
- Inferior opthalmic vein
Into pterygoid plexus or cavernous sinus
