EXERCISE 7

ENDOSCOPIC PRECOCHLEARIFORM HFN DECOPRESSION

STEP D – magnified view of geniculate ganglion
The geniculate ganglion view should be magnified

STEP E – Important relations
The GSPN,1st part of FN, geniculate crest (Fakushimabar) and geniculate ganglion relations are noted.

STEP F – Angle between 1st and 2nd part of FN.
The 70 degree angle between 1st and 2nd parts of FN is noted, they are at same level.

STEP G – Exposure of distal part of labyrinthine FN.
The distal part of 1st FN travels around geniculate crest, but the proximal part of 1st FN travels between ampulla of SSSC and the cochlea.
The relation between FN and ampulla of SSC is noted (very close)
.

RULE OF 2 – The meatal segment of facial nerve is usually 2 mm anterior and superior to the superior vestibular nerve.

Labelling:
TT – Tensor tunnel
GG – Geniculate ganglion
CP – Cochleariform process
GSPN – Greater superficial petrosal nerve

1FN – Labyrinthine FN
FB – Fakushima bar
FG – Facial gutter
A – Angle (70degree) between 1st and 2nd parts of FN
ALSS – Ampullaof LSSC
VW – Vestibular wall
HFN – Horizontal FN
GC – Geniculate crest
ASSC – Ampulla of SSC