Dissection of left ear from superior aspect

Tympanic cavity and inner ear in relation to external ear, superolateral view

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Image #61-2

Dissection of left ear from superior aspect

Tympanic cavity and inner ear in relation to external ear, superolateral view

Part of the petrous portion of the temporal bone has been ground away to demonstrate the internal auditory meatus, cochlea, semicircular canals and tympanic cavity. The posterior semicircular canal is obscured by a thin layer of bone but this has been transilluminated to show its position (15). The superior semicircular canal lies within the vertical edge of bone at 14.

1. Optic nerve (II)
2. Upper pointer: Oculomotor nerve (III) Lower pointer: Trochlear nerve (IV)
3. Periorbita (bony lateral wall of orbit removed)
4. Semilunar ganglion (trigeminal)
5. Temporalis muscle
6. Greater superficial petrosal nerve
7. Middle meningeal artery (cut off) and Lessor superficial petrosal nerve
8. Upper pointer: Cochlea Lower pointer: Geniculate ganglion facial nerve
9. Upper pointer: Malleus Lower pointer: Incus
10. Lateral wall of tympanic cavity above tympanic membrane
11. Tympanic antrum (opened from above)
12. Anterior margin of foramen magnum (in background of view)
13. Facial nerve (VII) within internal acoustic meatus
14. Ridge of bone supporting superior semicircular canal (not visible)
15. Position of posterior semicircular canal (exposed and illuminated posteriorly)
16. Lateral semicircular canal (note short segment of lateral semicircular duct lying within canal)
17. Auricle