SGW - eye 2 Flashcards
what is an orbital blow-out fracture?
direct impact to the orbit e.g. fist / ball causing sudden increase in INTRA-ORBITAL pressure
what does the rapid rise in intra-orbital pressure from orbital blow-out fracture cause?
rapid rise in pressure is transmitted through the walls of the orbit
with inferior, thin wall (floor) and maybe medial often fracturing
orbital rim remains intact
what happens as the floor of the orbit fractures?
contents of the orbit e.g. ORBITAL FAT can prolapse through into the MAXILLARY SINUS
extra-ocular muscles (R III muscles) can also become trapped
how would the eye appear in an orbital blow-out fracture?
- sunken from some of the contents of the orbit (orbital fat + extra-ocular muscles) displaced
- eye cannot be elevated due to trapping of inferior rectus
why can an orbital blow-out fracture lead to reduced sensation over the cheek?
due to damage of infra-orbital branch of maxillary (V2) - which exits just below the orbit through infra-orbital foramen
why might suturing orbital blow-out fracture wounds be difficult?
any injury involving area near the medial angle of eye (angular vein) could involve injury to the lacrimal canaliculi and nasolacrimal duct
describe drainage of the lacrimal gland
lacrimal gland –> sweeped across eyes by eyelids –> lacrimal puncta –> lacrimal canaliculi –> lacrimal sac –> nasolacrimal duct –> inferior meatus –> choanae –> nasopharynx –> oesophagus –> stomach
where does angular vein receive blood from? drains to?
from the superior, inferior palpebral, external nasal, and INFRAORBITAL veins.
It drains into the superior ophthalmic vein at angular vein and forms an important connection with the cavernous sinus
what happens if wound is repaired without consideration for the lacrimal drainage system immediately beneath, then what can happen?
the injured ducts can become stenosed as they heal
pt could be left with long-term problems with the excessive tearing (no draining of lacrimal gland secretions)
and recurrent conjunctivitis (dirt particles not drained) due to impedance of tear drainage
how should wounds through medial angle of eye be dealt with?
referred to a specialist
treatment may involve microsurgery and placing a stent through the canniculi / duct to ensure it remains patent as the wound heals
function of superior rectus?
eye up and out
out because of position of the muscle attachment, so naturally pull out - from orbital apex to limbus
superior oblique function?
abducts, depresses and internally rotates the eye
(down and in, intort)
(orbital apex –> lateral of superior rectus)
inferior oblique function?
extorsion (external rotation); elevation; abduction
(eye up and in - in to ABduct, therefore, without it = down and out)
(orbital apex –> inferior to lateral rectus)
medial and lateral rectus function?
medial = moves eye medially lateral = moves eye laterally
inferior rectus function?
eye down and out (eye sits in orbit pointing out, attachment from orbital apex to limbus)
