Chapter 15: Eyes Physical Examination 2022

Chapter 15: Eyes Physical Examination 2022 Eyelids - -two rapid window shades that further protect the eye from injury, strong light, and dust -upper eyelid is larger and more mobile Palpebral Fissure - elliptical open space between eyelids Canthus - corner of the eye, the angle where the lids meet Caruncle - -at the inner canthus -small, fleshy mass containing sebaceous glands Tarsal Plates - strips of connective tissue that gives upper eye lid its shape Meibomian Glands - -in the tarsal plates -modified sebaceous glands that secrete an oily lubricating material onto the lids -this stops the tears from overflowing and helps form an airtight seal when lids are closed Conjunctiva - -transparent covering on the exposed part of the eye -thin mucous membrane folded like an envelope between the eyelids and the eyeball Lacrimal Apparatus - -provides constant irrigation to keep conjunctiva and cornea moist and lubricated Extraocular Muscles - give the eye both straight and rotary movement What are the four straight (rectus) muscles? - -superior -inferior -lateral -medial What 3 cranial nerves stimulate the movement of the EOM (extraocular muscles)? - -abducens nerve (VI): innervates the lateral rectus muscle (which abducts the eye) -trochlear nerve (IV): innervates the superior oblique muscle -oculomotor nerve (III): innervates all the rest- the superior, inferior, and medial rectus and the inferior oblique muscles Three concentric coats of the eye - -outer fibrous sclera -middle vascular choroid -inner nervous retina Scelra - -tough, protective white covering -continuous anteriorly with the smooth, transparent cornea, which covers the iris and pupil Cornea - -thin, transparent, and very sensitive to touch Corneal Reflex - -blinking in response to corneal stimulation Choroid - has a dark pigment to prevent light from reflecting internally and is heavily vascularized to deliver blood to the retina Pupil - -is round and regular -its size is determined by a balance between the parasympathetic and sympathetic chains of the ANS -stimulation of the parasympathetic branch, through cranial nerve III, causes constriction of the pupil -stimulation of the sympathetic branch dilates and elevates the eyelids.......