Send the link below via email or IMCopy
Present to your audienceStart remote presentation
- Invited audience members will follow you as you navigate and present
- People invited to a presentation do not need a Prezi account
- This link expires 10 minutes after you close the presentation
- A maximum of 30 users can follow your presentation
- Learn more about this feature in our knowledge base article
Do you really want to delete this prezi?
Neither you, nor the coeditors you shared it with will be able to recover it again.
Make your likes visible on Facebook?
Connect your Facebook account to Prezi and let your likes appear on your timeline.
You can change this under Settings & Account at any time.
Transcript of Temporal Bone
•Petromastoid portion is the petrous and mastoid portions together.
•The mastoid portion, which forms the inferior, posterior part of the temporal bone located behind the ear, is prolonged into the conical mastoid process, or tip. Many air cells are located within the mastoid process that connects to the middle ear. •The petrous portion, often called the petrous pyramid, contains the organs of hearing and balance including the mastoid air cells. It is conical or pyramidal and is the thickest, densest bone in the cranium. The upper border of the petrous portion is commonly referred to as the petrous ridge and it projects anteriorly and toward the midline from the area of the EAM (external acoustic meatus). The petrous ridge of these pyramids corresponds to the level of an
important external landmark, the TEA (the top of the ear attachment). Near the center
of the petrous pyramid on the posterior surface just superior to the jugular
foramen is an opening or orifice termed the internal acoustic meatus
(IAM), which serves as a passageway for facial and vestibulocochlear
(auditory) nerves of hearing and equilibrium. The temporal bone articulates with the parietal, occipital, and the sphenoid bones of the cranium, and the zygomatic and mandible of the facial bones. •Mandibular fossa – depression in the squamous part below
the zygomatic process and is the region where the mandibular
•Jugular foramen – opening along the junction of the petrous part of the temporal bone and occipital bone and serves as the passageway for the jugular vein and the glossopharyngeal, vagus, and accesspry nerves.
•Foramen lacerum – large hole found at the junctions of the temporal, sphenoid, and occipital bones. It is filled by cartilage in adults and doesn’t serve as a passageway for blood vessels or nerves.
•Carotid canal – hole on inferior surface of petrous part, anterior to the jugular foramen and is a passageway for the internal carotid artery
•Mastoid notch – the depression on the medial side of the mastoid process and is the attachment for digastric muscle that moves the hyoid bone and opens the mouth (depresses the mandible)
•Stylomastid foramen – small hole on the mastoid part between the styloid and the mastoid process – is the passageway for the facial nerve and stylomastoid artery
•Mastoid foramen – hole posterior to the mastoid process and may
not be present or in the same location – is the passageway for
the vein to the transverse sinus and artery to the
dura mater Due to the result of the increased use of CT for cranial imaging, the following petromastoid portion projections were removed:
the axiolateral oblique projection of the modified law method, Stenvers method, and the Arcelin method - that leaves us with only the AP Townes and the Submentovertex (SMV) positioning for the temporal bone.
With the Townes and the SMV, the only significant anatomy for positioning would be the external acoustic meatus, or EAM. With that, it will help with figuring out the different cranial lines like the OML and the IOML and how far to center from the EAM. •The paired R & L temporal bones are complex structures housing the delicate organs for hearing and balance.
•It is irregular in shape and are situated on each side of the base of the cranium between the greater wings of the sphenoid bone and the occipital bone
•Form a large part of the middle fossa of the cranium and a small part of the posterior fossa
•Each temporal bone consists of a squamous portion, a tympanic
portion, a styloid process, a zygomatic process, and a
petromastroid portion (the mastoid and petrous portions)
that contains the organs of hearing and balance. •Squamous portion is the thin upper portion of the temporal bone that forms part of the wall of the skull. This part of the skull is quite thin and is therefore the most vulnerable portion of the entire skull to fracture. It also forms a part of the side wall of the cranium and has a prominent arched process, the zygomatic process, which projects anteriorly to articulate with the zygomatic bone of the face and complete the easily palpable zygomatic arch.
•Tympanic portion is situated below the squama and in front of the mastoid and petrous portions of the temporal bone. This portion forms the anterior
wall, inferior wall, and part of the posterior walls of the EAM, external
acoustic meatus – in other words, it surrounds the ear canal. The
EAM, external acoustic meatus, is approx. ½ inch in length
and is an opening along the external surface of
the temporal part. Reference Used Merrill's Atlas of Radiographic positioning & Procedures, Vollume II
Textbook of Positioning and Related Anatomy by Bontrager, Sixth Edition
Getbodysmart.com for Temporal Bone Anatomy