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Extraocular muscles dr.gosai


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Extraocular muscles

Extraocular muscles dr.gosai

  2. 2. Bony Orbit Seven bones make up the bony orbit: Frontal  Zygomatic  Maxillary  Ethmoidal  Sphenoid  Lacrimal  Palatine 
  3. 3. Bony Orbit ROOF: FLOOR: The orbital roof formed The floor of the orbit from both the orbital plate of the frontal bone and the lesser wing of the sphenoid bone. Above the roof is cranial cavity. Contains: Lacrimal fossa for lacrimal gland is formed from three bones and related to maxillary sinus:    Maxillary Palatine Orbital plate of the zygomatic It contains: Infraorbital groove Attachment of Inferior oblique muscle
  4. 4. Bony Orbit MEDIAL WALL of the orbit is formed from four bones and related to lateral wall of nose:     Frontal process of the maxillary Lacrimal Orbital plate of the ethmoidal Lesser wing of the sphenoid  Lacrimal fossa for lacrimal sac. LATERAL WALL: Formed from two bones:   Zygomatic Greater wing of the sphenoid  Thickest and strongest  Lateral orbital tubercle (Whitnall’s tubercle) for attachment of lateral check ligament
  5. 5. Orbital Foramina  The optic foramen: Transmit Optic nerve and Ophthalmic artery  The supraorbital foramen, or notch: transmit supraorbital nerve and vessels  The zygomatic foramen: Transmit Zygomatic nerve  Infraorbital canal: Transmit Infraorbital nerve and vessels  Superior orbital fissure: Transmit occulomotor nerve, trochlear nerve, abducent nerve, Branches of Ophthalmic nerve, Ophthalmic veins  Inferior orbital fissure: Maxillary nerve
  6. 6. Structures passing through superior orbital fissure
  7. 7. Extra ocular Muscles in the orbit
  8. 8. Extraocular Muscles The four recti and two oblique muscles All are supplied by oculomotor nerve III except superior oblique (Trochlear N) and lateral rectus (Abducent N)
  9. 9. Extra ocular Muscles in the Orbit Voluntary Muscles: 1. Four Recti – Superior, inferior, medial and lateral. 2. Two Oblique – Superior & inferior. 3. Elevator of upper eyelid – Levator palpebrae superioris. Involuntary Muscles: 1. Superior tarsal muscle – Deeper part of levator palpebrae superioris 2. Inferior tarsal muscle 3. Orbitalis muscle
  10. 10. Extra ocular Muscles
  11. 11. Extra ocular Muscles:Origin Common annular tendinous ring
  12. 12. Extra ocular Muscles:Origin Levator palpebrae superioris Superior Oblique Superior Rectus Lateral Rectus Medial Rectus Inferior Rectus Inferior Oblique
  13. 13. Levator Palpebrae Superioris         Origin: Orbital surface of lesser wing of sphenoid bone, anterosuperior to optic canal. Insertion: Splits in two lamina Superior lamina (voluntary) to Skin of upper eyelid & anterior surface of superior tarsal plate Inferior lamina (Muller’s muscle) (involuntary) to upper margin of superior tarsus (superior tarsal or muller’s muscle) & superior conjunctival fornix Nerve Supply : Oculomotor nerve (voluntary part); Sympathetic (involuntary part) Action: Elevation of upper eyelid. Damage to oculomotor nerve lead to paralysis of this muscle and leads to ptosis. Even damage to sympathetic fibers in Horner’s syndrome leads to partial ptosis due to paralysis of Muller’s muscle.
  14. 14. Extra ocular Muscles Insertion: on the sclera Recti – on sclera in front of equator ; distance from cornea – SR = 7.7mm, LR = 6.9mm. IR = 6.5mm; MR = 5.5mm. Superior Oblique – Behind the equator on sclera in superolateral posterior quadrant, between the recti superior and lateralis. Inferior Oblique : - Behind the equator on sclera in inferolateral posterior quadrant, between the recti superior and lateralis.
  15. 15. Nerve Supply: Abducent (VI cranial) nerve supplies lateral rectus
  16. 16. Nerve Supply: Trochlear (IV cranial) nerve supplies superior oblique
  17. 17. Nerve Supply  Superior, Inferior & Medial Recti; Levator palpebrae superioris and Inferior Oblique Muscles are supplied by Oculomotor ( III cranial) Nerve
  18. 18. Movements of Eyeball  Along vertical axis : Lateral rotation (Abduction) & Medial rotation (Adduction)  Along Transverse axis : Elevation & Depression  Along anteroposterior axis : Intortion (cornea moves medially from 12 O'clock position) & Extortion (cornea moves laterally from 12 O'clock position)
  19. 19. Actions of Recti Muscles
  20. 20. Actions of Recti Muscles Superior rectus: Elevation; Adduction; Intortion Lateral rectus: Abduction; Inferior rectus: Depression; Adduction; Extortion Medial rectus: Adduction;
  21. 21. Actions of Oblique Muscles Superior Oblique: : Depression, Abduction, Intortion Inferior Oblique : Elevation, Abduction, Extortion
  22. 22. Actions of Oblique Muscles Superior Oblique: : Intortion Anteroposterior axis Inferior Oblique : Extortion
  23. 23. Actions of Oblique Muscles Vertical axis Both oblique muscles pulls posterolateral quadrant anteromedially; thus abduct the eyeball.
  24. 24. Movements of Eyeball Recti muscles: straight muscles •Superior rectus: oculomotor nerve •Adduction, elevation, intorsion •Inferior rectus: oculomotor nerve •Adduction, depression, extorsion •Medial rectus: oculomotor nerve •Adduction •Lateral rectus: abducent nerve •Abduction •Superior oblique: trochlear nerve •Abduction, depression, intorsion •Inferior oblique: oculomotor nerve •Abduction, elevation, extorsion
  25. 25. Applied Anatomy  Abnormal deviation of eyeball is known as Squint (Strabismus).  Paralysis of Lateral rectus due to damage to Abducent nerve leads to Medial Squint. Medial Squint  Damage to Occulomotor nerve leads to paralysis of all muscles of eye except Superior oblique and lateral rectus leading to Lateral Squint and Ptosis-Dropping of Eyelid.  Damage to Trochlear nerve cause paralysis of superior oblique muscle causing diplopia while looking downwards. Lateral Squint and Ptosis -Dropping of Eyelid.
  26. 26. Inferior Oblique Superior Oblique Lateral rectus Medial rectus Superior rectus Inferior rectus
  27. 27. Horner’s syndrome • Causes: interruption of sympathetic pathway like multiple sclerosis, syringomyelia, traction of stellate ganglion by cervical rib, ganglion metastatic lesion. • Signs: • Constriction of pupil (miosis) due to paralysis of dilator pupillae • Slight drooping of eyelid (ptosis) due to paralysis of Muller’s muscle (Part of Levator palpebrae superioris) • Enophthalmos (Retraction of eyeball) due to paralysis of Orbitalis muscle which support the eyeball • Loss of sweating (anhydrosis) damage to sympathetic fibers to sweat glands • Loss of ciliospinal reflex