The Orbit Flashcards
What is the roof, medial wall, lateral wall, and floor of the orbit?
roof: frontal bone, lesser wing of sphenoid
medial wall: ethmoid, lacrimal, maxilla
lateral wall: zygomatic, greater wing of sphenoid
floor: mxilla, zygomatic, palatine
The lacrimal groove is an important landmark in the orbit. What is it between and what does it hold?
between the lacrimal and maxillary bones; lacrimal sac
The optic canal is an important landmark in the orbit. Where at in the orbit is it located and what does it transmit?
at the apex, in the lesser wing of sphenoid; transmits optic nerve and ophthalmic artery
In regards to the composition of the eyelids, a thin palpebral part of the ___ ___ lies anterior to the tarsi and is separated from the skin by a thin layer of loose CT
orbicularis occuli
In regards to the composition of the eyelids, a “skeleton” of the eyelids is formed by dense CT plates known as the superior and inferior ___ for the upper and lower lids respectively
tarsus
In regards to the composition of the eyelids, the ___ glands are embedded in the tarsi, with openings in the margins of the eyelids.
tarsal
What do the tarsal glands secrete?
an oily substance that prevents overflow of tears in normal production
In regards to the composition of the eyelids, the ___ ___ ligament connects the tarsi to the medial margin of the orbit and is the origin for the orbicularis occuli. The ____ ____ ligament connects the tarsi to the lateral margin of the orbit
medial palpebral; lateral palpebral
In regards to the composition of the eyelids, an orbital ____ is continuous with the periosteum and at the level of the orbital margin, extends into the eyelids and fuses with the tarsi
septum
In regards to the composition of the eyelids, the aponeurosis of the ___ ____ ____ attaches to the superior tarsus. Smooth muscle fibers froming the ___ ___ muscle also inserts here. These muscles elevate the eyelid.
levator palpebrae superioris; superior tarsal
The ____ lines the inner surface of the eyelids
conjunctiva
Sebaceous and sweat glands present in the eyelids have openings by the ____
eyelashes
Eyelashes are arranged in 2-3 rows at the free margin of the eyelid from the ___ ____ to the level of the ____ ____. Just medial to this site in the lid margin is the lacrimal ____
lateral canthus; plica semilunaris; papilla
What is the basic structure of the eyelids?
skin, SC tissue, striated muscle, tarsus and orbital septum, smooth muscle, and conjunctiva
The lacrimal gland is situated in the ____ part of the ____ part of the orbit
anterior; superolateral
There are numerous ducts that drain the lacrimal gland, opening into the lateral part of the ____ ____
superior fornix
The tear collects ____ in the lacrimal lake. The lacrimal lake contains an elevated mucosal site called the lacrimal ____ and a vertical fold of conjunctiva, the semilunar fold
medially; caruncle
Tears then flow into the lacrimal ___ of the upper and lower eyelids via their openings, the lacrimal ___.
canaliculi; puncta
The lacrimal puncta are on the elevations known as lacrimal ____, located just medial to the eyelashes
papillae
The lacrimal canaliculi empty into the lacrimal ____ located in the lacrimal groove adjacent to the nose
sac
The lacrimal sac continues inferiorly as the _____ duct that empties into the nasal cavity, guarded by a valve
nasolacrimal
The lacrimal gland receives sensory from the ____ nerve, a branch of the ophthalmic nerve (V1)
lacrimal
The lacrimal gland receives parasympathetic innervation by preganglionic fibers from the ____ nerve synapsing the ____ ganglion.
facial (greater petrosal nerve); pterygopalatine
Postganglionic axons travel ____ then ___ to reach the lacrimal gland
V2; V1
Sympathetic innervation of the lacrimal gland is via postganglionic axons from the ___ ____ ganglion -> deep petrosal nerve + great petrosal nerve = the nerve of the ___ ___ and reach the pterygopalatine ganglion in the pterygopalatine fossa
superior cervical; pterygoid canal
The outer, white, fibrous layer of the globe of the eyeball is the ____.
sclera
The ___ of the eyeball is avascular and is highly sensitive to touch, while the ___ is the site of attachment to extrinsic muscles and is pierced by vessels and nerve
cornea; sclera
The middle, vascular layer of the eyeball (urea) has 3 parts. What are they?
the choroid, ciliary body, and iris
This is the largest part of the vascular layer of the eyeball. It provides the inner retinal layer with an oxygen supply and nutrients
choroid
This is the anterior continuation of the choroid, forming a ring-like thickening that contains muscles as we’ll as vessels, and connects to the iris.
ciliary body
Folds of tissue project from the inner surface of the ciliary body forming ciliary processes that are attachment sites for the ___ via ___ fibers that form the suspensory ligament of the lens, and also secrete aqueous humor
lens; zonular
The ___ projects from the ciliary body as a circular aperture that lies on the anterior surface of the lens. It is the site for color of the eyes and contains muscle fibers that can either increase or decrease the pupil.
iris
Muscle fibers arranged in a circular pattern in the iris form the ___ ____ and are innervated by parasympathetic fibers. Muscle fibers arranged radially form the ____ ___ which is innervated by sympathetic fibers
sphincter pupillae; dilator pupillae
The inner layer of the eyeball is the ___ which consists of a large posterolateral optic part and a smaller anterior non-visual part. The two parts are continuous as a jagged line, the ora serrata.
retina
This part of the retina is sensitive to light and has two layers: an outer pigmented layer attached to the choroid and an inner neural layer attached to the pigmented layer only at the optic nerve and ora serrata
optic part
What occurs in the condition known as detached retina?
the inner neural layer separates from the pigment layer