Orbital Contents Flashcards
How does the location of the ciliary glands and the tarsal glands differ?
Why does blood pool in the eyelid with injury to the area?
There is a loose connective tissue layer just under the skin which allows for accumulation of blood as in a black eye
What is the function of the orbicularis oculi muscle?
it surrounds the orbit as a sphincter and is a facial muscle under voluntary control of the facial nerve.
It helps close the eyelid
What are the tarsal plates?
The tarsi are thin plates of fibrous CT in each lid
the upper is larger
they are attached to the palpebral ligaments laterally and medially and to the orbital septum
What is the orbital septum?
palpebral fascia
it’s fibrous membrane that attaches to the margins of the bony orbit
for the upper lid, it joins the tendon of the leavot palpebrae muscle and attaches to the superior tarsus
In the lower lid it also attaches to the tarsus
Ultimately, it forms a barrier between the inside and outside contents of the orbit
Define palpaebral and bulbar conjunctiva/conjuncitval sac
the conjunctiva in general is a mucous membrane deep to the tarsi and septum that lines the eyelids
the palpebral portion is thick, red and lines the insdie of the eyelids
the bulbar portion is over the sclera - it’s thin and transparent (over the cornea only the epithelial part is present)
the conjunctival sac is a space lined with conjuncitva that lies in front of the eye when the lids are closed
Where does the levator palpebrae muscle originate and insert?
It originates from bone above the optic foramen
inserts via a broad aponeurosis onto the anterior surface of the superior tarsus muscle, whose tendon penetrates the the orbital septum
What two types of muscles are associated with the levator palpebrae muscle?
the levator palpebrae superioris is a skeletal muscle
the superior tarsal muscle (muller’s muscle) is smooth muscle
How is the levator palpebrae innervated?
the levator palpebraae is innervated by the occulomotor nerve
What is Horner’s syndrome?
Horner’s syndrome is an interruption of sympathetic nerves inducing ptosis, pupillary constriction, flushin of the face and anhidrosis
How does the sensory innervation of the upper and lower eyelids differ?
sensory innervation is from the palpebral branches of the supraorbital, supratrochlear, infratrochlear and lacrimal branches of V1 (trigeminal) and palpebral branche sof the infraorbital of V2
What is the major blood supply and lymphatics to the eyelids?
arteries: lacrimal and ophthalmic arteries both have palpebral branches (veins similar to arteries)
lympnatics; lymph from the upper lid drains to the superficial parotid and superficial cervical nodes; lower lid tends to drain to the submandibular nodes
What glands are infected in a sty?
It’s a suppurative inflammation of the ciliary (sebaceous) glands or a meibomina (tarsal) gland
What is conjunctivitis?
Inflammation of the bulbar and palpebral conjunctiva - may be caused by bacteria, viruses, irritating fumes, or allergies
more common in children
Injury to what two nerves may produce ptosis?
lesion of the oculomotor nerve or sympathetic nerves innervating the smooth muscle of the superior tarsus muscle (Muller’s muscle)
What nerves are involved in the blink reflex?
facial nerve and trigeminal nerve (V1)
Where is the lacrimal gland located?
In the lacrimal fossa on the sueprior lateral aspect of the roof of the orbit
(separated form the eyeball by the levator palebrae and lateral rectus muscles)
What sensory nerve fibers reach the lacrimal gland?
the sensory supply is via the lactrimal nerve of the trigeminal V1
How do the autonomic secretory fibers reach the lacrimal gland?
the secretomotor fibers from the facial nerve (via the greater petrosal nerve)
the facial nerve carries preganglionic fibers to the pterygopalatine ganglion
postganglionic fibers leave thorugh the ygomatic branch of the maxillary (V2) to the communicating branch leading to the alcrimal nerve that leads to the lacrimal gland
