[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) › Temporal bones

[Skeletal system](https://durgical.com/en/anatomy/system/skeletal-system/) · [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/)

# Temporal bones

The temporal bones sit at the sides and [base of the skull](https://durgical.com/en/anatomy/occipital-bone/) around the ears; they house the hearing and balance organs and form the jaw joint socket.

Official name: Temporal bone

[See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=head_neck&select=temporal_bone&side=r)

Opens in the Durgical app, no sign-up needed.

## What it is

The bones at the sides and base of the skull, around the ears; they contain the middle and inner ear and the mastoid.

## What it does

House the hearing and balance organs and form the jaw joint socket.

## Key points

- At the [pterion](https://durgical.com/en/anatomy/pterion/) the squamous temporal meets the frontal, parietal and sphenoid bones; it is the thinnest part of the side of the skull, over the anterior branch of the [middle meningeal artery](https://durgical.com/en/anatomy/middle-meningeal-artery/)
- Petrous fractures are classed as otic capsule sparing or violating (older terms: longitudinal, transverse); capsule-violating ones more often cause deafness and facial palsy
- Signs of a petrous fracture: bruising over the mastoid (Battle sign), blood behind the [eardrum](https://durgical.com/en/anatomy/tympanic-membrane/) (haemotympanum) and CSF otorrhoea
- The facial nerve leaves through the stylomastoid foramen between the mastoid and styloid processes; in infants the mastoid is small and the nerve lies superficial

## Key facts

**Joints with**
Parietal, occipital, sphenoid, zygomatic (arch); [mandible](https://durgical.com/en/anatomy/mandible/) (TMJ)

**Landmarks**
Squamous, petrous and tympanic parts; mastoid and styloid processes; mandibular fossa; internal and external acoustic meatuses; carotid canal; stylomastoid foramen; articular tubercle; petrotympanic fissure (chorda tympani); arcuate eminence; tegmen tympani; trigeminal impression; jugular fossa

## Relations

**Above**
[Temporal lobe](https://durgical.com/en/anatomy/middle-temporal-gyrus/) on the squamous part and the floor of the middle cranial fossa; the [trigeminal ganglion](https://durgical.com/en/anatomy/trigeminal-ganglion/) in a depression near the petrous apex

**Medial**
Petrous apex next to the [cavernous sinus](https://durgical.com/en/anatomy/cavernous-sinus/) and [foramen lacerum](https://durgical.com/en/anatomy/foramen-lacerum/); the [internal acoustic meatus](https://durgical.com/en/anatomy/internal-acoustic-meatus/) carries the [facial nerve (VII)](https://durgical.com/en/anatomy/facial-nerve/) and the [vestibulocochlear nerve (VIII)](https://durgical.com/en/anatomy/vestibulocochlear-nerve/)

**Behind**
[Sigmoid sinus](https://durgical.com/en/anatomy/sigmoid-sinus/) in a deep groove on the inner mastoid surface; the [cerebellum](https://durgical.com/en/anatomy/anterior-quadrangular-lobule/) against the posterior surface of the petrous part

**Below**
[Jugular foramen](https://durgical.com/en/anatomy/jugular-foramen/) ([internal jugular vein](https://durgical.com/en/anatomy/internal-jugular-vein/), IX, X, XI) and [carotid canal](https://durgical.com/en/anatomy/carotid-canal/) under the petrous part; the [parotid gland](https://durgical.com/en/anatomy/parotid-gland/) and the facial nerve below the [stylomastoid foramen](https://durgical.com/en/anatomy/stylomastoid-foramen/)

**Lateral**
[Temporalis](https://durgical.com/en/anatomy/temporalis-muscle/) over the squama; the [auricle](https://durgical.com/en/anatomy/auricle/) and [ear canal](https://durgical.com/en/anatomy/external-acoustic-meatus/); the mandibular condyle in the mandibular fossa

## How to find it

The mastoid process is felt behind the ear lobe and the zygomatic arch in front of the ear. The pterion lies roughly two finger-breadths above the zygomatic arch and a thumb's breadth behind the frontal process of the [zygomatic bone](https://durgical.com/en/anatomy/zygomatic-bone/).

## Examination

- Tuning forks after a head injury: Weber heard louder on the injured side with a negative Rinne there points to conductive loss (blood in the middle ear, broken ossicular chain); Weber going to the other side with a positive Rinne points to sensorineural loss from an inner ear fracture
- Facial movement as soon as possible after the injury (raising the brows, closing the eyes tightly, showing the teeth): weakness of a whole half of the face suggests the facial nerve is hurt in its bony canal, and noting whether it was immediate or delayed guides management

## On imaging

High-resolution CT of the temporal bones (thin slices, bone algorithm) shows fractures, the ossicles, the facial canal and the mastoid cells; MRI shows the nerves in the internal acoustic meatus, for example a vestibular schwannoma.

## Clinical notes

- An extradural haematoma under the pterion can push the uncus over the [tentorium](https://durgical.com/en/anatomy/tentorium-cerebelli/), compressing the oculomotor nerve: a fixed, dilated pupil on the side of the clot
- Acute mastoiditis after otitis media can break through to a postauricular abscess that pushes the ear forward, or spread inward to the sigmoid sinus and meninges
- Gradenigo syndrome: infection of the petrous apex with abducens (VI) palsy, deep facial pain in V1 territory and a discharging ear
- In facial palsy after a temporal bone fracture, immediate onset suggests the nerve is cut; delayed onset suggests swelling, which has a better outlook

## Anatomical variants

- Superior semicircular canal dehiscence: the bone over the canal, in the floor of the middle cranial fossa, is very thin or missing; loud sounds or straining can set off vertigo, and some people hear their own pulse or eye movements
- Petrosquamous (Körner) septum: a bony plate that separates superficial from deep mastoid air cells; in mastoid surgery it can be mistaken for the medial limit, leaving deeper diseased cells behind
- Mastoid aeration varies from many large air cells to dense bone with few cells; a poorly aerated mastoid is common in people with long-standing middle ear disease

## Development

The mastoid process is barely present at birth and grows over the first years as the sternocleidomastoid pulls on it; the mastoid air cells extend after birth.

## Related conditions

- [Epidural haematoma](https://durgical.com/en/conditions/epidural-haematoma/)
- [Osteopetrosis](https://durgical.com/en/conditions/osteopetrosis/)
- [Acute mastoiditis](https://durgical.com/en/conditions/acute-mastoiditis/)
- [Basilar skull fracture](https://durgical.com/en/conditions/basilar-skull-fracture/)

## Test yourself

Think of the answer, then tap the question to see it.

## What are the classic signs of a fracture through the petrous part of the temporal bone?

Bruising over the mastoid (Battle sign), blood behind the eardrum (haemotympanum) and CSF otorrhoea.

## Which type of petrous temporal bone fracture more often causes deafness and facial palsy?

The otic capsule violating fracture (older term: transverse), compared with the capsule sparing (longitudinal) type.

## Through which foramen of the temporal bone does the facial nerve leave the skull, and why is it vulnerable in infants?

The stylomastoid foramen, between the mastoid and styloid processes; in infants the mastoid is small, so the nerve lies superficial.

## What triad defines Gradenigo syndrome of the petrous temporal bone?

Infection of the petrous apex with abducens (VI) palsy, deep facial pain in V1 territory and a discharging ear.

## In facial palsy after a temporal bone fracture, what does the timing of onset suggest?

Immediate onset suggests the facial nerve is cut; delayed onset suggests swelling, which has a better outlook.

[Add to my cards (5)](https://durgical.app/estudiar/?add=/en/anatomy/temporal-bone/)

Educational information, not medical advice. For any symptom, see a health professional.

## Its names

**Official Latin (TA2)**
os temporale TA2 641

**Official Spanish (DeCS)**
Hueso Temporal DeCS D013701

**English (TA2)**
Temporal bone

## Related

- [TMJ disc](https://durgical.com/en/anatomy/articular-disc-of-temporomandibular-joint/)
- [Cochlea](https://durgical.com/en/anatomy/cochlea/)
- [Incus](https://durgical.com/en/anatomy/incus/)
- [Malleus](https://durgical.com/en/anatomy/malleus/)
- [Semicircular canals](https://durgical.com/en/anatomy/semicircular-canals/)
- [Sigmoid sinus](https://durgical.com/en/anatomy/sigmoid-sinus/)
- [Stapes](https://durgical.com/en/anatomy/stapes/)
- [Vestibule](https://durgical.com/en/anatomy/vestibule/)

Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=14079); [Anatomy, Head and Neck, Skull](https://www.ncbi.nlm.nih.gov/books/NBK499834/); [Anatomy, Head and Neck, Temporal Region](https://www.ncbi.nlm.nih.gov/books/NBK482497/).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/anatomy/temporal-bone/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/temporal-bone/