Temporal bone

Temporal bone, by the way, is the most complex bone in our body. It is embryologically formed by the fusion of 11 ossification centers^* that incorporate the peripheral part of the audio-vestibular system and provide all necessary channels and openings for multiple cranial nerves & blood vessels passing through it.

^* Navjot Singh. Prenatal growth of cranium, facial and oral structures. Chapter 3 from the Textbook of Orthodontics, ed. Gurkeerat Singh, third ed. JAYPEE, 2015, p21–27.

Download JPG image — Os temporale dxt. ex situ & in situ.

Postero-medial aspect of temporal bone with the terminology markup — Dorsomedial aspect of right temporal bone.
The list of terms:
Pars squamosa (facies cerebralis) – Squamous part (cerebral surface)
Pars petrosa (pyramis) – Petrous part (pyramid) of temporal bone
Pars petrosa (processus mastoideus) – Petrous part (mastoid process)
Incisura parietalis – Parietal notch
Fissura petrosquamosa – Petrosquamous fissure

Lateral view of right temporal bone with the terminology markup — Lateral aspect of the right temporal bone.
The list of terms:
Pars squamosa (facies temporalis) – Squamous part (temporal surface)
Processus mastoideus (pars petrosa) – Mastoid process (petrous part)
Pars tympanica – Tympanic part
Incisura parietalis – Parietal notch
Crista supramastoidea – Supramastoid crest
Processus zygomaticus – Zygomatic process
Fissura tympanomastoidea – Tympanomastoid fissure
Fissura tympanosquamosa – Tympanosquamous fissure
Fissura petrosquamosa – Petrosquamous fissure
Fissura petrotympanica (Glaseri) – Petrotympanic fissure
Porus acusticus externus – Opening of external acoustic meatus
Sulcus tympanicus – Tympanic groove
Incisura tympanica – Tympanic notch
Meatus acusticus externus – External acoustic (auditory) meatus

Medial view of right temporal bone with the terminology markup — Medial aspect of the right temporal bone.
The list of terms:
Margo sphenoidalis – Sphenoidal border
Margo parietalis – Parietal border
Incisura parietalis – Parietal notch
Margo occipitalis – Occipital border
Margo posterior partis petrosae – Posterior border of petrous part of the temporal bone
Margo superior partis petrosae – Superior border of petrous part of the temporal bone
Apex partis petrosae – Apex of petrous temporal bone
Porus acusticus internus
Meatus acusticus internus – Internal acoustic (auditory) meatus
Apertura externa aqueductus vestibuli – External opening of vestibular aqueduct
Sulcus sinus sigmoidei – Groove for sigmoid sinus
Foramen mastoideum – Mastoid foramen
Impressiones digitatae – Digitate impressions
Juga cerebralia – Cerebral ridges of cranium

Anterior view of right temporal bone with the terminology markup — Anterior aspect of right temporal bone.
The list of terms:
Fissura petrosquamosa – Petrosquamous fissure
Canalis musculotubarius – Musculotubal canal
Semicanalis m. tensoris tympani – Semicanal for tensor tympani muscle
Semicanalis tubae auditoriae (auditivae) – Semicanal for the auditory tube
Canalis caroticus – Carotid canal
Apertura interna canalis carotici – Internal opening of carotid canal
Hiatus canalis n. petrosi minoris – Hiatus of canal for lesser petrosal nerve
Hiatus canalis n. petrosi majoris – Hiatus of canal for greater petrosal nerve

Top view of right temporal bone with the terminology markup — Top aspect of right temporal bone.
The list of terms:
Fissura petrosquamosa – Petrosquamous fissure
Tegmen tympani – Roog of tympanic cavity
Eminentia arcuata – Arcuate eminence
Impressio trigeminalis – Trigeminal impression
Apex partis petrosae – Apex of petrous temporal bone
Hiatus canalis nervi petrosi minoris – Hiatus of canal for lesser petrosal nerve
Sulcus n. petrosi minoris – Groove for lesser petrosal nerve
xHiatus canalis nervi petrosi majoris – Hiatus of canal for greater petrosal nerve
Sulcus n. petrosi majoris – Groove for lesser petrosal nerve
Sulcus sinus petrosi superioris – Groove for superior petrosal sinus

Posterior view of right temporal bone with the terminology markup — Posterior aspect of right temporal bone.
The list of terms:
Porus acusticus internus
Meatus acusticus internus – Internal acoustic (auditory) meauts
Apertura externa aqueductus vestibuli – External opening of vestibular aqueduct
Fossa subarcuata – Subarcuate fossa
Sulcus sinus petrosi superioris – Groove for superior petrous sinus
Sulcus sinus sigmoidei – Groove for sigmoid sinus
Sulcus sinus petrosi inferioris – Groove for inferior petrous sinus
Incisura jugularis – Jugular notch
Processus intrajugularis – Intrajugular process
Processus styloideus – Styloid process
Vagina processus styloidei – Sheath of styloid process
Incisura mastoidea – Mastoid notch
Sulcus a. occipitalis – Groove for occipital artery
Foramen mastoideum – Mastoid foramen

Bottom view of right temporal bone with the terminology markup — Bottom aspect of right temporal bone.
The list of terms:
Tuberculum articulare – Articular tubercle
Fossa mandibularis – Mandibular fossa
Fissura tympanosquamosa – Tympanosquamous fissure
Fissura petrotympanica – Petrotympanic fissure
Canaliculus chordae tympani – Canaliculus for chorda tympani
Processus mastoideus – Mastoid process
Incisura mastoidea – Mastoid notch
Sulcus a. occipitalis – Groove for occipital artery
Foramen mastoideum – Mastoid foramen
Processus styloideus – Styloid process
Foramen stylomastoideum – Stylomastoid foramen
Canalis nervi facialis – Facial canal
Apertura externa canalis carotici – External opening of carotid canal
Canalis caroticus – Carotid canal
Fossa jugularis – Jugular fossa
Canaliculus mastoideus – Mastoid canaliculus
Fossula petrosa – Petrosal fossula
Canaliculus tympanicus – Tympanic canaliculus
Apertura externa canaliculi cochleae – External opening of cochlear canaliculus

Markup for the canalis facialis within semi-transparent bone — Canalis facialis within the semi-transparent right temporal bone.
The list of terms:
Meatus acusticus internus – Internal acoustic (auditory) meatus
Canalis nervi facialis – Facial canal
Foramen stylomastoideum – Stylomastoid foramen
Geniculum canalis facialis – Genu of facial canal
Hiatus canalis nervi petrosi majoris – Hiatus of canal for greater petrosal nerve

Markup for the osseous labyrinth within the semi-transparent temporal bone — Internal acousttic meatus and the osseous labyrinth within the temporal bone
The red structure you see in the image above is the osseous labyrinth – the channel system surrounded by a thick cortical bone layer within the petrous part of the temporal bone. This cortical bone is one of the densest structure in our skeleton (petrous in Latin means stone-like), so the vestibular and hearing apparatus arranged in these channels is particularly well protected.
The list of terms:
Meatus acusticus internus – Internal acoustic (auditory) meatus
Cochlea
Vestibulum
Canales semicirculares – Osseous semicircular canals

Download JPG image — Cellulae mastoideae within the semi-transparent temporal bone. The lateral projection.

Cellulae mastoideae within the semi-transparent bone — Cellulae mastoideae within the semi-transparent temporal bone. The lateral projection.

Download JPG image — The complex view of some major internal structures of the temporal bone, including mastoid cells (yellow), the facial canal (green), labyrinth (red), tympanic cavity with canalis musculotubarius (magenta), and meatus acusticus internus (blue).

Interal structures of temporal bone — The complex view of some major internal structures of the temporal bone, including mastoid cells (yellow), the facial canal (green), labyrinth (red), tympanic cavity with canalis musculotubarius (magenta), and meatus acusticus internus (blue).

Temporal bones ex situ & in situ. 360° rotation.

First published: May/2019
Last update: 25/12/2023