Anatomy of the Eye

• The roof of the orbit is composed of

  • Lesser wing of the sphenoid bone
  • Orbital plate of the frontal bone
• Volume of the orbit

  • 30mL
• The roof of the orbit is intimately related to the

  • Frontal sinus
• The lateral wall is separated from the roof by the

  • Superior orbital fissure
• The roof is intimately related to the

  • Frontal sinus
• The lateral wall is composed of

  • Greater wing of the sphenoid
  • Zygomatic bone
• It is the strongest part of the bony orbit

  • Lateral wall
• The floor of the orbit is separated from the lateral wall by the

  • Inferior orbital fissure
• The floor of the orbit is composed of

  • Maxillary bone
  • Zygomatic bone
  • Palatine bone
• It is the weakest part of the orbit

  • Floor
• The floor is intimately related to the

  • Maxillary sinus
• In cases of trauma, orbital contents can herniate into the

  • Maxillary sinus
• The medial wall is intimately related to the

  • Ethmoid sinus
  • Sphenoid sinus
• The medial wall is composed of the (4)

  • Ethmoid bone
  • Sphenoid bone
  • Lacrimal bone
  • Maxilla
• Thinnest wall

  • Medial wall
• Superior orbital fissure

  • Apex
• The orbital apex is the site of origin of all the EOMS except for the

  • Inferior oblique
• Components of the lateral portion of the superior orbital fissure

  • Superior ophthalmic vein
  • Lacrimal nerve
  • Frontal nerve
  • Trochlear nerve
• Middle portion of the superior orbital fissure is composed of

  • Superior and inferior division of the oculomotor nerve
  • Nasociliary nerve
  • Abducent nerve
• Medial portion of the superior orbital fissure is composed of

  • Inferior ophthalmic vein
  • Sympathetic nerves
• The optic canal transmits the

  • Optic nerve
  • Ophthalmic artery
• Blood supply of the orbit comes from the (4)

  • Ophthalmic artery
  • Short posterior artery
  • Long posterior artery
  • Anterior ciliary artery
• It supplies the ciliary body

  • Long posterior artery
• It is derived from the muscular branches of the rectus muscles

  • Anterior ciliary artery
• Venous drainage of the orbit (4)

  • Superior and inferior ophthalmic veins
  • Vortex veins
  • Anterior ciliary veins
  • Central retinal veins
• The ophthalmic veins communicate with the cavernous sinus via the

  • Superior orbital fissure
• The ophthalmic veins communicate with the pterygoid venous plexus via the

  • Inferior orbital fissure
• Formed from the supraorbital and supratrochlear veins

  • Superior ophthalmic vein
• Danger triangle is from the

  • Root of the nose to the side of the lips
• Infection in the danger triangle will cause

  • Cavernous sinus thrombosis
• Size and volume of the eyeball

  • Size: approximately 24.5mm
  • Volume: 5mL
• Anterior eyeball is from the

  • Lens forward
• 2 chambers of the anterior eyeball

  Demarcation is the iris

  Anterior chamber: everything in front of the iris

  Posterior chamber: everything behind the iris
• Posterior segment of the eyeball is behind the

  • Lens
• Outer layer/fibrous layer

  • Cornea
  • Sclera
• Vascular layer

  • Uveal tract
• Neural layer

  • Retina
• 4 media that should remain transparent

  • Cornea
  • Aqueous humor
  • Lens
  • Vitreous gel
• It is a thin transparent mucous membrane that covers the posterior (palpebral) and anterior (bulbar) surface of the eyelid.

  • Conjunctiva
• Histology of the conjunctiva

  • 2-5 layers of stratified columnar epithelial cells