Pre-Practical 3 Flashcards
What are the 3 foramina of the orbit?
Optic foramen/canal
Superior orbital fissure
Inferior orbital fissure
What structures pass through the optic foramen?
The optic nerve (Cr N II) and the opthalmic artery
What structures pass through the superior orbital fissure?
The motor nerves (Cr N III, IV, VI) alongside the branches of V2
What structures pass through the inferior orbital fissure?
V3 and veins
What constitutes the fibrous coat of the eye and what do they do?
The lens which allows light to enter the eye and the sclera which allows attachment of the muscles moving the eyeball
What constitutes the vascular layer of the eye and what do they do?
Iris which controls the diameter of the pupil and so controls how much light enters the eye
Ciliary body suspends the lens and produces aqueous humor
Choroid which supplies the blood to the outer layers of the eye
What constitutes the sensory layer of the eye and what do they do?
Retina which has light sensitive rods and cones which enable us to see
Fovea centralis which is the spot in the retina with the greatest visual acuity due to the concentration of rods and cones
Describe the aqueous and vitreous humor
Aqueous - A watery fluid produced by the ciliary body which maintains intraocular pressure
Vitreous - A transparent gel which helps cushion the retina also produced by the ciliary body
What are the intrinsic muscles of the eye?
Ciliaris muscle - In the ciliary body
Constrictor pupillae
Dilator pupillae
What are the extrinsic muscles of the eye?
Lateral rectus Medial rectus Superior rectus Inferior rectus Superior oblique Inferior oblique
What is the nervous innervation of the extrinsic muscles of the eye?
Occulomotor (Cr N III) innervates all but the Superior Oblique and the Lateral Rectus. These are innervated by the Trochlear nerve (Cr N IV) and the Abducens nerve (Cr N VI) respectively
Where do the extrinsic muscles of the eye arise from?
The recti muscles arise from the apex of the orbit from an annular fibrous ring
The superior oblique arises from the roof of the orbit posteriorly
The inferior oblique arises from the floor of the orbit anteriorly
Which muscle elevates the eyelid and what closes it?
The levitator palpebrae superioris (LPS) elevates the eyelid while the orbiculis oculi closes the eyelid
Describe the drainage of the lacrimal apparatus the lacrimal gland’s innervation
Tears drain into the lacrimal sac which then drains into the inferior meatus
The lacrimal gland receives parasympathetic innervation from the facial nerve (Cr N VII)
What salivary glands secrete serous saliva and which secrete mucous and what colour are their staining?
Parotid = Serous = Dark staining Sublingual = Mucous = Light staining Submandibular = Mixed = Both
