Human

• Anatomy Of The Orbit & Eye
• Dr Ayida Al Wahaibi AY-22-23
• Bones forming the orbit

  • Frontal bone
  • Zygomatic bone
  • Maxillary bone
  • Sphenoid bone
  • Ethmoid bone
• Orbital foramina


  Openings in the bony orbit that allow structures to pass through
• Orbital foramina


  • Anterior ethmoid foramen
  • Optic canal
  • Superior orbital fissure
  • Opening of nasolacrimal duct (Lacrimal fossa)
  • Infraorbital sulcus
  • Inferior orbital fissure
  • Infraorbital notch
  • Supraorbital notch
• Optic nerve


  The second cranial nerve, considered part of the central nervous system
• Optic nerve anatomy


  1. Leaves the orbit via the optic canal

  2. Travels towards the optic chiasm

  3. Partial decussation (crossing) of fibers from the temporal visual fields of both eyes
• Contents of the orbit


  • Eyeball
  • Optic nerve
  • Extraocular muscles
  • Upper eyelid
  • Vessels
  • Nerves
• Extraocular muscles


  • Include the elevator of the eyelid and 6 extrinsic muscles of the eyeball
  • Arise from the posterior aspect of the orbit (except inferior oblique)
  • Inserted into the sclera
• Extraocular muscles


  • Lateral rectus
  • Medial rectus
  • Superior rectus
  • Inferior rectus
  • Superior oblique
  • Inferior oblique
• Paralysis of the medial rectus muscle


  Causes the eyeball to move to the lateral side
• Paralysis of the lateral rectus muscle

  Causes the eyeball to move to the medial side
• Periorbita


  Connective tissue enclosing the eyeball and its contents
• The roof of the orbit is broken away to reveal the periorbita and orbital contents
• Medial rectus


  Moves eyeball to medial side
• Medial rectus paralysis


  Eyeball moves to lateral side
• Lateral rectus


  Moves eyeball to lateral side
• Lateral rectus paralysis


  Eyeball moves to medial side
• Bony Orbit


  • Right orbit
  • Frontal sinus
  • Cribriform plate
  • Groove for infraorbital nerve
  • Hypophyseal Fossa
  • Zygomatic arch
  • Inferior orbital fissure
• Contents of the Orbit


  • Periorbita
  • Orbital fat
• Structures in the Orbit

  • Trochlear nerve
  • Frontal nerve
  • Supraorbital nerve
  • Supratrochlear nerve
  • Lacrimal nerve
  • Lacrimal gland
  • Levator palpebrae superioris
• Levator palpebrae superioris


  • Attached to the eyelid and NOT the eyeball
  • Retracts the eyelid to "open" the eye (can be either voluntarily or involuntarily)
• Muscles in the Orbit


  • Superior oblique
  • Superior rectus
  • Lateral rectus
  • Nasociliary nerve
  • Anterior ethmoid nerve
  • Posterior ethmoid nerve
• Structures on the Eyeball

  • Optic nerve
  • Short ciliary nerves
  • Medial rectus muscle
  • Ophthalmic artery
  • Superior ophthalmic vein
• Structures at the bottom of the Orbit


  • Ophthalmic artery
  • Ophthalmic vein
  • Ciliary ganglion
  • Inferior division of oculomotor nerve
  • Inferior rectus muscle
  • Inferior oblique muscle
• Orbital Floor


  • Made up of the zygomatic and maxillary bones
  • Holds the infraorbital nerve
  • Has the zygomatic foramen (infraorbital foramen) which accepts the zygomatic branch of the infraorbital nerve
• Elevation


  Movement of the eye around the horizontal axis so that it is looking upward
• Muscles for Elevation


  • Superior rectus
  • Inferior oblique
• Depression


  Movement of the eye around the horizontal axis so that it is looking downward
• Muscles for Depression


  • Inferior rectus
  • Superior oblique
• Adduction


  Movement of the eye around the vertical axis so that it is looking toward the nose
• Muscle for Adduction


  • Medial rectus
• Abduction


  Movement of the eye around the vertical axis so that it is looking laterally
• Muscles for Abduction


  • Lateral rectus
  • Superior oblique
  • Inferior oblique
  • Superior rectus
  • Inferior rectus
• Muscles of the Eye


  • Levator palpebrae superioris
  • Superior rectus
  • Superior oblique
  • Medial rectus
  • Lateral rectus
  • Inferior rectus
  • Inferior oblique
• Nerve Supply


  • Oculomotor nerve (III)
  • Trochlear nerve (IV)
  • Abducens nerve (VI)
• Superior oblique paralysis


  Eyeball moves abnormally
• Ophthalmic artery


  • Branches from the internal carotid just before it enters into the formation of the Circle of Willis
  • Enters the orbit with the optic nerve through the optic foramen
  • Gives rise to the central artery of the retina
• Ciliary Ganglion


  • Peripheral ganglion of the parasympathetic system of the eye
  • Situated between the optic nerve and the lateral rectus muscle
  • Receives afferent fibers from the eye through the nasociliary nerve (of V1)
• Nerve Fibers in the Ciliary Ganglion


  • Postganglionic parasympathetic fibers from oculomotor nerve
  • Sensory fibers from nasociliary nerve
  • Postganglionic sympathetic fibers from carotid plexus