Bits & Pieces

Question 1

What seperates the ethmoid air cells from the orbit?

Answer 1

Lamina Papyracea or Orbital Lamina

Its the lateral bony plate of the ethmoid bone seperating the air cells from the orbit

Question 2

Which part of the facial nerve innervates bilaterally?

Answer 2

The part to the forehead

Question 3

Describe the arrangement of nerves in the IAM?

Answer 3

Split into 4 quadrants:

• Post-Inf = Inferior Vestibular
• Post-Sup = Superior Vestibular
• Ant-Inf = Cochlear
• Ant- Sup = Facial

(7up Coke Down = VII nerve superior and Cochlear nerve inf)

Question 4

Describe the structure of the cochlea:

Answer 4

Scala Tympani (Tympanic Duct) runs around the Scala Media (cochlear Duct) which contains the Organ of corti on which the hair cells are found.

ST = Perilymph
SC = Endolymph

Question 5

Describe the semi-circular Canals:

Answer 5

Three:

• Sup/Ant (Vertical in the Sagittal Plane so nodding/tipping head)
• Post (Coronal Plane)
• Lateral (Transverse plane so does turning of head)

These orientations are not very precise

Question 6

Which end of the cochlea is high frequency sound detected at?

Answer 6

Basal turn i.e. closer to the Oval window.

So does that mean low Frequency sounds travel further round?