Temporal bone anatomy

Question 1

Name the 5 parts of the temporal bone

Answer 1

1. Squamous
2. Mastoid
3. Petrous (contains inner ear, IAC, petrous apex)
4. Tympanic
5. Styloid
6. Zygomatic process

Question 2

Name the major components of the temporal bone

Answer 2

EAC
Middle ear - Mastoid
Inner Ear
Internal auditory canal
Petrous apex
CN7 CN8
ICA
Internal jugular bulb

Question 3

How common is pneumatised petrous apex?

Location of Eustachian tube?

Name the 3 parts of the middle ear

Answer 3

About 1/3 of the population

Between the carotid canal and the foramen ovale

Hypotympanum
Mesotympanum (middle ear proper)
Epitympanum (Attic)

Question 4

Name 3 key structures of the posterior wall of the Mesotympanum

Name 3 key structures of the middle wall of the Mesotympanum

Answer 4

Facial nerve recess
Pyramidal eminence
Sinus tympani

Tympanic segment CN7
Oval window
Round window

Question 5

What are the borders of the epitympanum?

What is the border of the hypotympanum?

Answer 5

Above the line from the scutum tip to tympanic CN7

Below the line from tympanic annulus to the base of cochlear promontory

Question 6

What is the tegment tympani?

What is the Prussak space?

Answer 6

The roof of the middle ear

The lateral epitympanic recess

Question 7

Name 3 key structures of the mastoid sinus

Answer 7

Aditus ad antrum (epitympanum to mastoid antrum)
Mastoid antrum (large central mastoid air cell)
Tegmen Mastoideum (roof of mastoid air cells)

Question 8

Origin and attachment:

tensor tympani m.

Stapedius m.

Answer 8

Cochleariform - tensor tympani m. - neck MALLEUS

Pyramidal eminence - stapedius m.- neck STAPES

Question 9

Foot of stapes sits on

Answer 9

Oval window

Question 10

Bony structure in the cochlea?

Answer 10

Spiral lamina seperates Scala vestibuli from Scala tympani

Question 11

What is a 2 window view

Answer 11

Trasverse oblique recon through axial view shows OVAL + ROUND WINDOW NICHE

Question 12

Greater superficial petrosal nerve location

Answer 12

After the facial nerve takes the turn from the geniculate ganglion whatever is left and goes anteriorly is the GSP n

Question 13

Facial nerve branches

Answer 13

1. Motor nucleus - Extracranial facial nerve for facial expression
   + Stapedius n.
2. Superior salivatory nucleus (Parasympathetic) gives the greater superficial petrosal nerve (lacrimation)
3. Solitary tract nucleus(taste) + Parasympathetics give CHORDA TYMPANI = anterior 2/3 tongue taste and parasymp to submandibular and sublingual glands)

Question 14

Chorda tympani location

Answer 14

Immediately medial the tympanic membrane, passes between the ossicles

Question 15

What goes through the tympanic canaliculus?

Answer 15

The tympanic branch of CN IX Jacobson n.

Question 16

Membranous labyrinth - endolymph

Perilympharic spaces

Answer 16

ENDOLYMPH:
Vestibule
Semicircular canals/ducts
Scala media
Endolymphatic duct & sac

PERILYMPH:
Surrounding vestible
Around semicircular canals
SCALA TYMPANI & VESTIBULI

Question 17

Which chambers of the cochlea are visible?

Answer 17

Scala vestibuli

Scala Tympani

Question 18

Describe hearing

Answer 18

Movement of Stapes ->fluid waves oval window

Cochlear recess wave to Scala Vestibuli

Waves in the perilymph of Scala vestibuli transmitted via vestibular membrane to the endolymph of Cochlear duct (SCALA MEDIA)

This causes displacement of Basilar membrane and moves hair cell receptors Organ Corti
This movement generates electric potentials

High freq cochlear base
Low freq cochlear apex