Lecture 4 - The Skull

Question 1

What is the Cranium?

Answer 1

• also known as the skull
• the skeletal structure of the head that supports the face & protects the brain

Question 2

How can the cranium be broken down?

Answer 2

• broken down into the neurocranium & the viscerocranium

Question 3

What is the neurocranium?

Answer 3

• broken down into 7 total bones

Question 4

What are the 7 bones of the neurocranium?

Answer 4

• frontal bone
• parietal bone (2)
• temporal bone (2)
• sphenoid bone
• occipital bone

Question 5

What is the frontal bone?

Answer 5

• the single bone that forms the forehead

Question 6

What is the parietal bone?

Answer 6

• forms most of the upper lateral side of the skull
• paired bones that join together at the top of the skull

Question 7

What is the temporal bone?

Answer 7

• forms the lower lateral side of the skull

Question 8

What are the bony landmarks of the temporal bone?

Answer 8

• external auditory meatus
• mastoid process
• styloid process
• zygomatic arch
  - half temporal bone, half zygomatic bone

Question 9

What is the sphenoid bone?

Answer 9

• a single, complex bone of the central skull but also extends laterally to contribute to the sides of the skull
• serves as a “keystone” because it joins with almost every other bone of the skull

Question 10

What is the occipital bone?

Answer 10

• forms the posterior skull & posterior base of the cranial cavity

Question 11

What are the bony landmarks of the occipital bone?

Answer 11

• External Occipital Protuberance
  - Important for muscle attachment
• Occipital Condyles
  - Attaches the skull to the vertebral bone

Question 12

What is the viscerocranium?

Answer 12

• the facial bones
• broken down into 15 bones

Question 13

What are the 15 bones of the viscerocranium?

Answer 13

• mandible
• ethmoid bone
• vomer
• maxilla (2)
• inferior nasal concha (2)
• zygomatic bone (2)
• palatine bone (2)
• nasal bone (2)
• lacrimal bone (2)

Question 14

What is the mandible?

Answer 14

• forms the lower jaw & is the only moveable bone of the skull
• at birth the mandible is paired but they fuse during the first year to a single bone

Question 15

What are the bony landmarks of the mandible?

Answer 15

• Mandibular condyle & fossa
• the fossa is part of the temporal bone which forms the temporomandibular joint (TMJ)

Question 16

What is the ethmoid bone?

Answer 16

• forms the roof & lateral walls of the upper nasal cavity, the upper portion of the nasal septum, & contributes to the medial wall of the orbit
• also forms the floor of the anterior cranial cavity

Question 17

What is the vomer bone?

Answer 17

• an unpaired bone which forms the posterior-inferior part of the nasal septum

Question 18

What is the maxilla bone?

Answer 18

• a pair of bones that form the upper jaw, much of the hard palate, the medial floor of the orbit, & the lateral base of the nose

Question 19

What is the inferior nasal concha?

Answer 19

• a right & left bone that project into the nasal cavity space from the lower lateral wall
• it is the largest of the nasal conchae

Question 20

What is the zygomatic bone?

Answer 20

• also known as the cheekbone
• paired bones that form much of the lateral wall of the orbit & the lateral-inferior margins of the anterior orbital opening

Question 21

What is the palatine bone?

Answer 21

• paired bones that contribute to the small areas to the lateral walls of the nasal cavity & the medial wall of each orbit
• the largest region is the horizontal plate which join together at the midline to form the posterior quarter of the hard palate

Question 22

What is the nasal bone?

Answer 22

• paired bones that join together to form the bony base of the nose
• they also support the cartilages that form the lateral walls of the nose

Question 23

What is the lacrimal bone?

Answer 23

• a small bone that that forms the anterior, medial wall of the orbit
• the anterior portion of the lacrimal bone forms a shallow depression called the lacrimal fossa

Question 24

What are sutures?

Answer 24

• how the cranial bones are united

Question 25

What are the 4 main sutures?

Answer 25

• sagittal
• coronal
• lambdoidal
• squamosal

Question 26

What is the sagittal suture?

Answer 26

• joins the right & left parietal bones

Question 27

What is the coronal suture?

Answer 27

• joins the frontal bone to the parietal bones

Question 28

What is the lambdoidal suture?

Answer 28

• joins the occipital bone & the parietal bones

Question 29

What is the squamosal suture?

Answer 29

• joins the temporal bone to the parietal bone

Question 30

What are the 3 cranial fossae ?

Answer 30

• anterior cranial fossa
• middle cranial fossa
• posterior cranial fossa

Question 31

What is the anterior cranial fossa?

Answer 31

• the most interior & shallowest
• overlies the orbits & contains the frontal lobes of the brain
• bounded by the frontal bone, which forms the majority of the floor

Question 32

What is the middle cranial fossa?

Answer 32

• deeper & situated posterior to the anterior fossa
• has several openings for the passage of blood vessels & cranial nerves

Question 33

What is the posterior cranial fossa?

Answer 33

• the most posterior & deepest portion
• contains the cerebellum of the brain