TEMPORAL BONE

Question 1

Temporal bone

Answer 1

Forms the lower part of the lateral wall of the skull

Formed by the fusion of:

1. Pars SQUAMOSA
2. Pars PETROSA, Processus mastoideus
3. Pars TYMPANICA

Question 2

TEMPORAL BONE

Pars PETROSA and TYMPANICA

Answer 2

• Enclose the inner & the middle ear
• at the base of the skull these part Related to the basal part of the Occipital bone
• in CA: Surura occipitotympanica -> the 2 bones unite at this suture
• In others: Fissura petrooccipitalis Separates the two bones

Question 3

Temporal bone

- PARS SQAMOSA

Answer 3

= formation of the wall of the Cranial cavity

Parts of the Pars Squamosa:

A. FACIES CEREBRALIS - inner surface

1. Sulci Arteriosi et venosi
2. Impressiones Digitatae
3. Juga Cerebellaris
4. Crista Tentorica - in small ru

B. FACIES TEMPORALIS - outer

1. Processus zygomaticus
   - lateral and rostrally
   - forms the Arcus Zygomaticus with the tenporal process of the zygomatic bone!
   - FACIES Articularis for the mandibular joint on the Ventral surface
2. TUBERCULUM Articulare
   - forms the mandibular joint in front
   - rostral to the fossa articularis
3. Fossa MANDIBULARIS
   - forms the mandibular joint
   - for the condyle of mandible
   - Facies Articularis
4. Processus RETROSRTICULARIS
   - behind the fossa MANDIBULARIS
5. Foramen RETROARTICULARE
   - in eq, bo, ca
   - external opening of the MEATuS temporalis
6. Processus occipitalis
   - behind the origin of the ZYGOMATIC process
   - forms a surure with the Occipital bone
   - on its outer surface runs the CRISTA TEMPORALIS
7. Processus RETROTYMPANICUS
   - surounds the external auditory mestus caudally
8. MEATUS Temporalis
   - formed by the pariettal bone and Proc. Occipitalis
   - contain veins from the dorsal SINUS of dura mater
9. Fossa Temporalis
   - area surrounded by Linea Temporalis

Question 4

Temporal bone
PARS PETROSA
General

Answer 4

• caudovental part of temporal bone

INNER SURFACE: facies medialis
- faces the Cranial cavity

1. PORUS ACCUSTICUS INTERNUS
   - leads into the MEATuS accusticus internus via the FUNDUS MEATUS ACCUSTICUS INTERNUS
   - CRISTA transversa arises from the FUNDUS

Question 5

Temporal bone
Pars PETROSA
Structures FACIES Medialis (inner surface)

Answer 5

INNER SURfACE (facies medialis)
1. PORUS ACCUSTICUS INTERNUS

a. Area N. facialis —> entrance of the facial canal

B. Area Cochlea —> for the passage of the cochlear branches of the n.vestibulocochlearis

C. Area Vestibularis Superior (dorsalis)

D. Area Vestibularis inferior (Ventralis) —>
For the passage of the vestibular branches of the vestibulocochlear nerve

Question 6

Temporal bone
Pars petrosa
Fascies Ventralis

Answer 6

• Forms the lower part of the medial wall of the tympanic cavity of the middle ear
  Presents:

A. PROMONTORIUM
B. FENESTRA VEStIBuLI (OVALIS)
C. FENESTRA cochleae (Rotundum)

Question 7

Temporal bone
Pars petrosa
Structures

Answer 7

1. Processus Styloideus
   In eq,bo
   - provides attachment for the hyoid bone
2. Foramen STYLOMASTOIDEUM
   - exit of Canalis facialis (facial canal)
   - in ca: between the pars tympanica and the mastoid process
   - in eq, bo: between the styloid and Mastoid process

Question 8

Temporal bone

PARS tympanica

Answer 8

Lies at the base of the temporal bone

1. BULA TYMPANICA
   - Encloses the lower region of the CAVUM TYMPANI
   - Part of the middle ear
   - SEPTUM BULLAE in ca
2. BONY MEATUS ACUSTICUS EXTERNUS
   - Extends laterally from the upper part of the tympanic bulla
   - Ends at the PORUS MEATUS ACCUSTICUS EXTERNUS
3. VAGINA PROCESSUS STYLOIDEI
   - in eq, bo
   - Surrounds the Processus styloideus
4. PROCESSUS MUSCULARIS
   - projects from the mediorostral wall of the bula tympanica
   - in ca insignificant, taking the form of a very short thorn
   - in small ru, eq = long rod
   - in OX = the base is broad
5. FISSURA PETROTYMPANICA
   - opens from the tympanic cavity
   - btw pars TYMPANICA et PETROSA
   - Passage of the CHORDAE TYMPANI of the facial nerve
6. PARS OSSEA TUBA AUDITITIVA
   - LIES medial to the muscularis process
   - connection btw the TYMPANIC CAVITY and NASOPHARYNX
7. CANALIS MUSCULOTUBARIUS
   A. Semicanalis Tubae Auditiva - for Tuva auditiva into the tympanic canal
   B. Semicanalis m.tensor tympani - for m.tensor tympani
   C. Septum CANALIs musculotubari
8. CANALIS CAROTIcUS
   - in ca
   - on the medial wall of the tympanic bulla
   - for the A.Carotis INT
9. FOSSA CEREBELLARIS
   - depression DORSAL to the MEATuS ACCUSTICUS internus
   - for Cerebellum
10. FOSSA Subarcuata!!!!!
    - in car
    - deep depression to the PORUS ACCUSTICUS internus

Question 9

Temporal bone
Pars TYMPANICA
CAVUM TYMPANI

Answer 9

In the Middle Ear
- CAVUM TYMPANI

Comprises:

1. A CENTRAL CAVITY (MESOTYMPANICUM)
   - its lateral wall bears the ANULUS TYMPANICUS (tympanic ring)
   - Anulus tympanicus accomodates the membrana TYMPANICA
2. RECESSUS EPITYMPANICUS (EPITYMPANICUS)
   - LODGES the:
   A. Malleus
   B. Incus
   C. Stapes
   D. Lenticular bone
3. BULLA TYMPANICA (HYPOTYMPANICUM)
   - in ca, Devides into CELLULAE TYMPANICAE

PARS TYMPANICA ….

1. AQUEDUCTUS VESTIBULI
   - canal for the DUCTUS ENDOLYMPHATICUS
   - Apertura externa aqueductus vestibuli
2. CANALICULUS COCHLEAE
   - canal for the DUCTUS PERILYMPHATICUS
   - apperrura externa canalis Cochleae