What is the temporal bone?

The temporal bone: the base of the skull

Forming the lateral-inferior region of the skull, the temporal bone is an even and symmetrical bone. Because of its position, this bone protects the temporal lobe of the brain and the ear. Also, it contributes to the development of the temporomandibular joint.

Definition and anatomy of the temporal bone

An irregularly shaped bone, the temporal bone protects the temporal lobe of the brain, the cranial nerves that pass through it, as well as the middle ear and inner ear. In anatomical terms, it is composed of three parts: the squamous, tympanic, and petromastoid, along with two bony processes, the zygomatic and the styloid. Let's take a closer look.

The scaly portion

In the temporal bone, the scaly portion represents the largest bone section. It performs a number of functions, including:

  • it initiates the zygomatic process;
  • it has a groove through which the central meningeal artery passes;
  • it contains the mandibular condyle, which makes up the temporomandibular joint and forms the glenoid fossa;
  • it allows temporal muscle insertion;
  • it forms the lateral walls of the middle cerebral fossa.

The tympanic portion

The tympanic part of the temporal bone, which has a horseshoe shape, is located under the scaly portion and higher than the styloid process. The tympanic portion consists of the anterior, posterior, and inferior parts of the external auditory canal and the posterior part of the glenoid fossa.

The petrous portion

Combined, the petrous and mastoid portions make up the petromastoid portion. The petrous part is located between the sphenoid bone and occipital bone, and it functions to protect the structures of the middle and inner ear. Mastoid, on the other hand, is the bony portion of the temporal bone behind the ear, which houses a number of important muscles, including the sternocleidomastoid muscle.

The zygomatic process

The zygomatic process is a bony protrusion originating on the scaly part of the temporal bone and articulated with the zygomatic bone to form the so-called temporal process. The zygomatic process houses some fibers of the masseter muscle, one of the four muscles involved in chewing.

The styloid process

The styloid process is the bony protrusion that arises from the lower portion of the temporal bone. Several muscles and ligaments are located within the styloid process, which is located just below the external auditory canal. Fractures and impertrophy can occur in the temporal styloid process.

Relations of the temporal bone

Since the temporal bone has a particular position, it is connected to different body parts, including the skull bones, muscles, joints, ligaments, nerves, and vascular vessels. Let's see them in detail.

Muscles

The following muscles are related to the temporal bone:

  • the temporal muscle;
  • the masseter muscle;
  • the sternocleidomastoid muscle;
  • the digastric muscle;
  • the splenius muscle of the head;
  • the stiloglossus muscle;
  • the stylohyoid muscle;
  • the stilopharyngeal muscle.

Joints

The cranial sutures are fibrous joints that join the skull's bones together. Together with the temporomandibular joints, they are located within the temporal bone. 

There are five sutures in the temporal bone, namely:

  • the suture of the scaly layer;
  • the spheno-squamous suture;
  • the peri-mastoid suture;
  • the occipito-mastoid suture;
  • the temporo-zygomatic suture.

On the other hand, the temporomandibular joint allows opening, closing, and movement of the mouth, such as during chewing.

Ligaments

The ligaments that attach to the temporal bone are:

  • the stylohyoid ligament;
  • the stylomandibular ligament;
  • the lateral ligament of the TMJ. 

Nerves

In terms of the nervous system, the temporal bone is associated with:

  • the middle cerebellar fossa;
  • the cerebellum;
  • the motor eye III;
  • the trigeminal V;
  • the assistant VI;
  • the facepiece VII;
  • the acoustic VII;
  • the pharyngeal gloss IX.

Vessels

The following vessels are connected to the temporal bone:

  • the internal carotid artery;
  • the middle meningeal artery;
  • the jugular vein;
  • the lateral sinus;
  • the superior and inferior petrosal sinuses.

The function of the temporal bone

What is the purpose of the temporal bone? Among its many functions, it is primarily responsible for protecting the temporal lobe of the brain as well as the cranial nerves. In addition to forming the external auditory canal, the temporal bone houses the cockles, canals, and hearing organs. It also protects the middle and inner ear structures, which are more delicate.

Related pathologies

The temporal bone can be fractured just like any other bone in our body. Broken bones can cause pain in the right or left temporal bone, but other symptoms can also occur, such as dizziness and facial paralysis. Additionally, certain medical conditions can affect the temporal bone. For example, Paget’s disease of bone, a chronic disorder that disrupts the normal bone remodeling process, can lead to abnormal thickening or weakening of the temporal bone. This may result in symptoms such as hearing loss or cranial nerve compression. Moreover, an infection of the mastoid cells, known as mastoiditis, or a tumor can develop.

Amplifon online hearing test

Have you recently begun to notice any difficulties in hearing well? What are you waiting for? Try our online hearing test now!

Get support and advice

Book a free hearing test

Book now

Test your hearing online

Take the test

Find your nearest store

Find a store