Anatomy of the Temporal Bone

Question 1

IAC above and below structures

Answer 1

Above = arcuate artery
Below = Cochlear aqueduct

Question 2

Cochlear Aqueduct

Answer 2

from cochlea to arachnoid membrane - spread of meningitis

Question 3

Cochlea in relation to IAC

Answer 3

posterior to it = IAC

Inferior/spuerior = labarynthine

Question 4

Vestibular Aqueduct location/level

Normal Size?

Answer 4

at level of lateral SCC

0.5-1mm or same size of posterior SCC

Question 5

Porus vs. Fundus

Answer 5

Porus = medially
Fundus = laterally
- Fundus has the classic 7 up coch down configuration whereas porus does not

Question 6

LABARYNTHINE SEGMENT OF FN - WHATS ANTERIOR AND POSTERIOR TO IT

Answer 6

ANTERIOR - COCHLEA

POSTERIOR - LATERAL CANAL

Question 7

GSPN direction after geniculate?

Answer 7

antero-medial

Question 8

LABARYNTHINE SEGMENT OF FN - WHATS ANTERIOR AND POSTERIOR TO IT?

Answer 8

ANTERIOR - COCHLEA

POSTERIOR - LATERAL CANAL

Question 9

Tensor Tympani - level on CT

Answer 9

at Cochlea and facial nerve is in mastoid portion

Question 10

Coronal CT - Tmypanic and Labarynthine segements are seen together (snake eyes
- what structure is below cochlea

Answer 10

below cochlea = carotid

Question 11

what is inferior to IAC?

Answer 11

Cochlea

Question 12

Reason for not doing Stapedectomy in Menieres

Answer 12

because saccule is adjacent to footplate and it can be enlarged due to hydrops so more chances of perilymph coming out

Question 13

In Stapectomy - what to look for

Answer 13

Round window ossification as patient can have successful surgery but still have conductive loss

Question 14

Routes to the Petrous Apex

Answer 14

Posterior Apex (posterior to IAC and labarynth) - retrolab, inferior lab, subarcuate artery
Anterior Apex (medial to cochlea) - infracochlear

Question 15

3 Types of Petrous Apex

Answer 15

1) Air filled
2) Marrow Filled
3) Sclerotic

Question 16

What tissue is hyperintense on T1 and T2

Answer 16

Fat