skull reject

What are the two major parts of the skull?

The cranium (8 bones) and the facial bones (14 bones).

What are the eight cranial bones?

Parietal (2), Temporal (2), Frontal, Occipital, Ethmoid, Sphenoid.

What are the 14 facial bones?

Nasal (2), Lacrimal (2), Palatine (2), Inferior nasal conchae (2), Maxillae (2), Zygomatic (2), Vomer, Mandible.

What is a mesocephalic skull?

An average skull with petrous pyramids forming about 47° to the MSP.

What is a brachycephalic skull?

A broad skull with petrous pyramids forming about 54° to the MSP.

What is a dolichocephalic skull?

A long/narrow skull with petrous pyramids forming about 40° to the MSP.

What is diploë?

The cancellous bone between the inner and outer tables of the skull.

What type of joints are skull sutures?

Synarthrotic (immovable) joints.

What does the sagittal suture separate?

The two parietal bones.

What does the coronal suture separate?

The frontal and parietal bones.

What does the lambdoidal suture separate?

The parietal and occipital bones.

What does the squamosal suture separate?

The temporal and parietal bones.

What are wormian bones?

Small accessory bones found within cranial sutures.

What is the bregma?

The junction of the coronal and sagittal sutures; corresponds to the anterior fontanel.

What is the lambda?

The junction of the sagittal and lambdoidal sutures; corresponds to the posterior fontanel.

What bones meet at the pterion?

Parietal, frontal, and sphenoid bones.

What is the vertex?

The highest point of the skull.

What does the AP Axial (Towne) projection best demonstrate?

The occipital bone, foramen magnum, dorsum sellae, and posterior clinoid processes.

What is a linear skull fracture?

A straight, sharply defined fracture line.

What is a depressed skull fracture?

A comminuted fracture with bone fragments pushed inward.

What is a hangman fracture?

A C2 fracture with anterior subluxation of C2 on C3 due to forceful hyperextension.

What is a compression fracture?

Collapse of spongy (cancellous) bone, commonly in vertebral bodies.

What is a blowout fracture?

A fracture of the orbital floor caused by a direct blow.

How many cranial bones are there?

Eight.

What are the eight cranial bones?

Frontal (1), Parietal (2), Temporal (2), Occipital (1), Ethmoid (1), Sphenoid (1).

What region does the frontal bone correspond to?

The forehead region.

What are the orbital plates of the frontal bone?

The horizontal portions that form most of the superior aspect of the bony orbits.

What are the frontal eminences?

Rounded prominences on the anterior frontal bone, lateral to the MSP.

What is the glabella?

The smooth prominence between the eyebrows.

Where are the frontal sinuses located?

Directly behind the glabella, between the tables of the skull.

What are the superciliary arches (ridges)?

The bony ridges under the eyebrow region.

What are the supraorbital margins?

The upper borders of the bony orbits.

What are the supraorbital notches/foramina?

Openings in the supraorbital margin for passage of the artery and nerve to the forehead.

What is the frontonasal suture?

The articulation between the frontal bone and the nasal bones; corresponds externally to the nasion.

What do the parietal bones form?

The vertex and part of the lateral walls of the cranium.

What suture is formed where the two parietal bones meet?

The sagittal suture.

What other sutures do the parietal bones help form?

Coronal, squamosal, and lambdoidal sutures.

What are parietal eminences?

Rounded prominences on the lateral surfaces of each parietal bone.

What part of the skull does the occipital bone form?

The posterior wall and the inferior part of the cranium.

What suture is formed where the occipital bone meets the parietal bones?

The lambdoidal suture.

What does the basilar portion of the occipital bone articulate with?

The basilar portion (clivus) of the sphenoid bone.

What structures are located on the lateral portions of the occipital bone?

Occipital condyles, hypoglossal canals, and jugular foramina.

What is the foramen magnum?

A large opening that transmits the medulla oblongata, which continues as the spinal cord.

What is the squamosal portion of the occipital bone?

The posterior, superior portion containing the external occipital protuberance (inion).

What is the external occipital protuberance also called?

The inion or occiput.

What anatomy does the AP Axial (Towne) projection best demonstrate?

The occipital bone and foramen magnum region.

What do the temporal bones form?

The lateral aspects of the cranium.

Where are the temporal bones located?

Between the greater wings of the sphenoid and the occipital bone.

What do the petrous portions of the temporal bones contain?

The organs of hearing.

What openings are found in the temporal bones?

Internal auditory meati and carotid canals.

What do the zygomatic processes of the temporal bones articulate with?

The zygomatic (facial) bones.

What forms the temporomandibular joints (TMJs)?

The mandibular fossae of the temporal bones and the mandibular condyles.

What are the temporal styloid processes?

Sharp, slender projections extending anteriorly and inferiorly from the temporal bones.

What is the external auditory meatus (EAM)?

The external opening of the ear canal.

What are the mastoid processes?

Bony projections inferior to the EAM containing air cells that communicate with the tympanic cavity via the mastoid antrum.

How many facial bones are there?

Fourteen.

What are the 14 facial bones?

Nasal (2), Lacrimal (2), Palatine (2), Inferior nasal conchae (2), Zygomatic (2), Maxillae (2), Vomer, Mandible.

What are the nasal bones?

Small, rectangular bones that form the bridge of the nose.

What forms the movable part of the nose?

Cartilage.

What suture is formed where the nasal bones meet?

The nasal suture.

What is the frontonasal suture?

The articulation of the nasal bones with the frontal bone; corresponds to the nasion externally.

What are the lacrimal bones?

The smallest facial bones; form part of the medial orbital wall.

What is the lacrimal groove?

A depression that accommodates the lacrimal (tear) duct.

What are the zygomatic bones also called?

Malar bones or cheekbones.

Where are the zygomatic bones located?

Inferior and lateral to the outer canthus of the eye.

What are the four processes of the zygomatic bone?

Frontosphenoidal, orbital, temporal, and maxillary processes.

What are the maxillae?

The second largest facial bones; form most of the upper jaw.

What do the maxillae form together?

Most of the hard palate and the floor of the nasal cavity.

What are the palatine processes of the maxillae?

Horizontal plates that form the anterior two‑thirds of the hard palate.

What do the maxillary sinuses contain?

Air-filled cavities located superior to the bicuspid teeth.

What forms the thin floor of the maxillary sinus?

The alveolar process.

What is the alveolar ridge/process?

The spongy ridge of bone containing tooth sockets.

What is the anterior nasal spine?

A projection that corresponds externally to the acanthion.

What is the infraorbital foramen?

An opening below the orbit, lateral to the nasal cavity.

What do the palatine bones form?

The posterior one‑third of the hard palate.

What shape are the palatine bones?

L‑shaped.

What do the horizontal parts of the palatine bones articulate with?

The palatine processes of the maxillae to complete the hard palate.

What do the vertical parts of the palatine bones articulate with?

The sphenoid bones.

What are the inferior nasal conchae?

Completely osseous structures located on the inferior lateral walls of the nasal cavity.

What is another name for the inferior nasal conchae?

Nasal turbinates.

Where is the vomer located?

Inferior to the perpendicular plate of the ethmoid bone.

What does the vomer form?

The posterior portion of the bony nasal septum.

What are the choanae?

The posterior openings into the nasopharynx, separated by the posterior vomer.

What is the mandible?

A U‑shaped bone; the largest facial bone and the only movable facial bone.

What is the mandibular symphysis?

The midline where the two halves of the mandible fuse after birth.

What are the mental tubercles?

Prominences at the inferolateral margin of the mandibular symphysis.

What is the mental protuberance?

The prominence at the lower portion of the mandibular symphysis.

What is the alveolar process of the mandible?

The spongy ridge of bone containing the tooth sockets.

What is the body of the mandible?

The horizontal portion.

What is the ramus of the mandible?

The posterior vertical portion.

What is the angle of the mandible?

The junction of the body and ramus; corresponds externally to the gonion.

What forms the temporomandibular joint (TMJ)?

The mandibular condyle articulating with the mandibular fossa of the temporal bone.

What is the coronoid process?

The anterior, superior projection of the ramus; serves as a muscle attachment and has no articulation.

What is the mandibular notch?

The deep notch between the condyloid and coronoid processes.

What is the mental foramen?

A small opening on the outer surface of the mandible below the second premolar; passage for the mandibular nerve.

What is the mandibular foramen?

An opening on the inner surface of the ramus for the mandibular nerve.