Answer
The temporal bone is located in the area of the skull just superior to the external ear.. Thisa bone forms the lower wall and part of the floor of the floor of the cranial cavity. Descrptions of the temporal bone often utilize a tetrapartite division: squamous part, tympanic part, mastoid process and pwetrous part
Squamous Part.
Tis is the flkat , vertical palpatable part bof the bone. It is encircled by the squamous sutre. It also bears two promonent fetures , the zygomatic processand the mandibular fossa, The zygomatic process extends anteriorly to form part of the zygomatic arch; ( cheekbone). The mandibular fossa is a bony depression where the mandible connects with the cranium.
The tympanic part
This is a small bony ring close to the external auditory meatus (n pathway from the outer ear to the eardrum). On its inferior surface, a slender bony styloid process projects downward from the temporal bone This provides a point of attachment for muscles of pharynx, tongue and larynx.
Work Step by Step
3. The mastoid part.
This part is located posterior to the tympanic part. It has a prominent bump under the ear lobe-- the mastoid process. The mastoid process is filled with tiny air sinuses, and it communicates with the middle ear. Infection of the mastoid process-- mastoiditis -- is a serous ailment that may work its way to the brain.
The mastoid notch is also a noteworthy feature of the mastoid part. It is a groove that is located medial to the mastoid process. It is of interest because it is the site of the origin of the digastric muscle. This muscle functions in opening of the mouth, and in the movement of the hyoid bone to facilitate swallowing.
Finally, the stylomastoid foramen which goes through both styloid and mastoid processes permits passage of the facial nerve (CN VII) and stylomastoid artery.
4. Part four is the Petrous Part
This is in the floor of the cranium-- it is a ridge that separates the middle cranial fossa from the posterior fossa.. It contains the middle and inner ear cavities, as well as the internal auditory meatus. This canal, it allows the passage of the vestibulocochlear nerve (CN VIII), which transmits impulses for hearing and balance from the inner ear to the brain
Two important foramina open in the inferior surface of the petrous part These are the carotid canal and the jugular foramen.
The carotid canal . Through this canal the carotid artery passes on its route to the brain. The position of the vessel is close to the ear, and as a result one can sometimes hear ones pulse with one's head resting on a pillow in bed.
The second opening is the jugular foramen; it is a large opening just medial to the styloid process . Blood from the brain, drained by the sigmoid sinus, passes through the jugular foramen into the internal jugular vein in the neck. Three cranial nerves also pass through the jugular foramen; these are the glossopharyngeal (CN IX), the vagus (CN X), and the accessory ( CN XI).
