1) anatomy of the orbit

Question 1

what is the orbit made out of

Answer 1

two bones - lesser wing of the sphenoid and frontal
located next to the anterior cranial fossa
(next to the frontal sinus )

the lateral wall - greater wing of the sphenoid bone and the zygomaticus

the floor concept of three bones - zygoaticus
maxillary
palantine

medial wall of the orbit - maxillary , lacrimal , ethmoid and phoned bone

Question 2

a part of the maxillary is heavily prone to something ?

Answer 2

posteromedial part of the maxillary bone is relatively weak maybe involved in blowout fractures

Question 3

the floor of the orbit also forms the what ?

Answer 3

roof of the maxillary sinus

Question 4

the medial wall of the orbit is perforated why ? and this leads to some complications

Answer 4

for nerves and blood vessels

for this reason orbital cellulitis is frequently secondary to ethmoidal sinusitis

Question 5

what are the two fissures in the orbit ?

Answer 5

inferioir orbital fissure

and superioir orbital fissure

Question 6

where is the inferior orbital fissure located

Answer 6

located posterioir of maxilla and greater wing of sphenoid

Question 7

where is the superior orbital fissure ?

Answer 7

located posteriorly between the greater and lesser wing of sphenoid

Question 8

what goes through the inferior orbital fissure

Answer 8

from the trigeminal ganglion - the maxillary nerve passing through the foramen rotundum ( sphenoid bone )

sensory nerves

giving rise to the zygomaticus nerve - innervate skin over the zygomatic and temporal bones

ascending branches from pterygopalantine ganglion (lacrimal nerve)

infraorbital artery - branches from the maxillary artery - external carotid artery (into infraorbital foramen)

inferioir ophthalmic vein

Question 9

the inferior orbital fissure communicates with what ?

Answer 9

the ptrygopalatine fossa

Question 10

the superior orbital fissure communicates with what ?

Answer 10

middle cranial fossa

Question 11

what is in the superior orbital fissure ?

Answer 11

from the ophthalmic nerve :

frontal nerve - supraorbital and supratrochlear nerve , not in the tendinous ring
sensory innervation of forehead , upper eyelid and frontal sinus

lacrimal nerve-
sensory innervation of the lacrimal gland

nasocillary from ophthalmic nerve and sympathetic fibres from carotid plexus
communicating branch to cillary ganglion

from the nasocilliary nerve - long cillary nerves - pierce the sclera - reach the iris contain sympathetic fibres to innervate the dilator muscle of the pupil for light reflex

from the nasocilliary nerve - posterioir ethrmoidal nerve - sphenoidal and ethmoidal air sinus sensory branches
and anterior ethmoidal nerves - mucous membrane of nasal cavity

then
infratrochlear nerve - sensory innervation of skin ,medial part of upper eyelid and adjacent nose

anterior ethmoidal nerve - supplies mucus membrane of the nasal cavity near the slit of crista galli

superioir ophthalmic vein

trochelar nerve

oculomotor nerve

abducens

superioir ophthalmic vein