CorpusHuman Anatomy
SkeletalBone

Temporal bone

Os temporale

A paired, complex bone of the side and base of the skull that houses the middle and inner ear, forms the mandibular fossa of the temporomandibular joint and contributes the posterior zygomatic arch.

Show on body map Skull — Lateral View Ear — Coronal Section

Overview

The temporal bone has four parts. The thin squamous part forms the lateral wall of the middle cranial fossa and gives off the zygomatic process (posterior half of the zygomatic arch); beneath its root lie the mandibular fossa and articular tubercle for the mandibular condyle. The tympanic part is a curved plate forming most of the bony external acoustic meatus. The dense petrous part (petromastoid), a pyramid between the middle and posterior cranial fossae, houses the cochlea, vestibule and semicircular canals, the tympanic cavity and the ossicles; its posterior surface bears the internal acoustic meatus, and its inferior surface the carotid canal. The mastoid part behind the meatus forms the mastoid process, pneumatised by mastoid air cells continuous with the middle ear via the mastoid antrum.

The slender styloid process projects anteroinferiorly; between it and the mastoid lies the stylomastoid foramen, the exit of the facial nerve. The mastoid process is absent at birth and develops after ≈2 years with the pull of sternocleidomastoid — so in infants the facial nerve is superficial and vulnerable.

Location

Lateral wall and base of the cranium, below the parietal bone.

Parts & subdivisions

  1. Squamous part
    Thin plate of the temple; forms part of the pterion.
  2. Zygomatic process
    Forms the posterior part of the zygomatic arch.
  3. Mandibular fossa and articular tubercle
    Articular surfaces of the temporomandibular joint.
  4. External acoustic meatus (bony part)
    Medial two-thirds of the ear canal in adults.
  5. Petrous part
    Houses the inner and middle ear; its apex borders foramen lacerum.
  6. Internal acoustic meatus
    Facial nerve (CN VII), vestibulocochlear nerve (CN VIII) and labyrinthine artery.
  7. Carotid canal
    Internal carotid artery and the internal carotid sympathetic plexus.
  8. Mastoid process and air cells
    Attachment of sternocleidomastoid, splenius capitis and longissimus capitis; air cells communicate with the middle ear.
  9. Styloid process
    Attachment of stylohyoid ligament and the styloglossus, stylohyoid and stylopharyngeus muscles.
  10. Stylomastoid foramen
    Exit of the facial nerve (CN VII) and entry of the stylomastoid artery.
  11. Petrotympanic fissure
    Transmits the chorda tympani from the middle ear to the infratemporal fossa.

Anatomy

Articulations

Parietal (squamous suture), occipital (occipitomastoid suture), sphenoid (sphenosquamous suture), zygomatic (temporozygomatic suture) and mandible (TMJ — synovial).

Ossification

Squamous and tympanic parts intramembranous; petrous part endochondral (from the otic capsule); the styloid from 2nd pharyngeal arch cartilage. Parts unite in the first year.

Function

  • Houses and protects the organs of hearing and balance
  • Forms the cranial component of the temporomandibular joint
  • Transmits the internal carotid artery, facial and vestibulocochlear nerves
  • Attachment for temporalis, masseter (via arch), sternocleidomastoid and neck muscles

Clinical significance

Mastoiditis

Spread of otitis media to the mastoid air cells: postauricular swelling, pushed-forward pinna; complications include sigmoid sinus thrombosis, meningitis and cerebellar abscess.

Petrous temporal fracture

Longitudinal fractures cause conductive hearing loss and haemotympanum; transverse fractures more often injure the facial nerve and cochlea. Battle sign (mastoid ecchymosis) appears after 1–2 days.

Eagle syndrome

An elongated styloid process or calcified stylohyoid ligament causes throat pain on swallowing or turning the head.

Compiled from standard anatomy and physiology references — see the Skeletal System sources. For education only; not medical advice.