1. Skull
Usually consists of 22 bones, all of which (except the lower jaw) are firmly interlocked along lines called “sutures”.
Cranium = 8 bones
Facial skeleton = 13 bones + lower jaw
Lower jaw bone is called the mandible, and is the only movable bone.

2. Cranium Functions: Encloses and protects the brain
Provides attachments for muscles that make chewing and head movement possible
Has air-filled, mucous-membrane-lined (??), sinus cavities
Cavities open to outside

3. Cranial Bones Frontal bone Parietal bones (2) Occipital bone
Temporal bones (2)
Sphenoid bone
Ethmoid bone

4. Cranial Bones, continued…..
Frontal bone
Anterior portion of skull above the eyes
Houses 2 frontal sinuses, one above each eye near the midline
Parietal bones
One on each side of the skull just behind the frontal bone
Form bulging sides and roof of cranium
Fused at midline (sagittal suture) and to frontal bone (coronal suture)
Start labeling skull diagrams from Lab Exercise 13 in Hole’s Lab Manual

5. Cranial Bones, continued…..
Occipital bone
Joins the parietal bones (lambdoidal suture)
Forms back of skull and base of cranium
Foramen magnum – opening at bottom of occipital bone for nerve processes to connect to spinal cord
Occipital condyles – rounded processes on each side of foramen magnum that articulate with 1st vertebra

6. Cranial Bones, continued…..
Temporal bones
On each side of the skull
Joins parietal bone (squamosal suture)
Form parts of sides and base of cranium
External auditory meatus (???)
Mandibular fossae – depressions in the temporal bone that articulate with condyles (???) of the mandible
What does “meatus” mean? (passage) What could the external auditory meatus be?

7. Cranial Bones, continued…..
Temporal bones, continued….
Below each external auditory meatus:
Mastoid process – rounded attachment for certain neck muscles
Styloid process – long, pointed anchor for muscles associated with tongue and pharynx
Zygomatic process
Projects anteriorly (???) from temporal bone, joins the zygomatic bone (“cheek bone”), and helps form prominence of the cheek

8. Cranial Bones, continued…..
Sphenoid bone
Wedged between several other bones in anterior portion of cranium
Has a central portion and 2 wing-like structures that extend laterally (???)
Helps form base of cranium, sides of skull, and sides of orbits (“eye sockets”)
Midline of sphenoid bone has a depression (sella turcica) that houses pituitary gland
Contains 2 sphenoidal sinuses

9. Cranial Bones, continued…..
Ethmoid bone
Located in front of sphenoid bone
Consists of 2 masses, one on each side of nasal cavity
Masses joined by thin cribriform plates (???)
Cribriform plates form part of nasal cavity roof.
Crista galli – triangular process between cribriform plates
Perpendicular plate
projects downward from cribriform plates
helps form nasal septum
Cribr = sieve (These plates have tiny openings.)

10. Cranial Bones, continued…..
Ethmoid bone, continued…..
Superior nasal concha and middle nasal concha - project inward from lateral portions of ethmoid bone toward perpendicular plate
Lateral portions of ethmoid bone contain small air spaces (ethmoidal sinuses)

11. Cranial Bones Diagrams
Whole class: Label cranial bones on the diagrams of the skull.
Choose a color for each of the bones in the cranium (EX: parietal bone = red).
Color the bones their assigned color in each diagram.

12. Facial Skeleton Maxillae (2) Form the upper jaw
Portions comprise the anterior (???) roof of the mouth (“hard palate”), the floors of the orbits (???), and the sides and floor of the nasal cavity.
Contain sockets of the upper teeth
“Maxillary sinuses”
Inside the maxillae, lateral (???) to nasal cavity
The largest of the sinuses

13. Facial Bones, continued….
Maxillae, continued….
“Palatine processes” fuse midline (???) to form anterior section of hard palate
Teeth are found in cavities in the “alveolar arch” (aka “dental arch”) formed by the “alveolar processes” projecting downward from the inferior (???) border of the maxillae.

14. Facial Bones, continued….
Palatine bones
Behind the maxillae
Horizontal portions form posterior (???) section of hard palate and floor of nasal cavity
Perpendicular portions help form lateral (???) walls of nasal cavity

15. Facial Bones, continued…..
Zygomatic bones (“???”)
Also help form lateral walls and floors of the orbits
Each bone has a “temporal process” that connects to the zygomatic process (forming the zygomatic arch).
Lacrimal bones
Thin, scale-like structure in medial wall (??) of each orbit between ethmoid bone and maxilla

16. Facial Bones, continued…..
Nasal bones
Long, thin, and nearly rectangular
Lie side by side and fused at midline to form bridge of nose
Vomer bone
Thin and flat
Along midline in nasal cavity
Joins perpendicular plate of ethmoid bone posteriorly (???) to form nasal septum

17. Facial Bones, continued…..
Inferior nasal conchae
Fragile, scroll-shaped bones attached to lateral walls (???) of nasal cavity
Support mucous membranes in nasal cavity
Mandible (“???”)
Upward projection at ends:
Posterior “mandibular condyle” articulates with mandibular fossae on _______ bone
Anterior “coronoid process” provides attachments for muscles for chewing
“Alveolar arch” – curved, superior (???) border that contains sockets for lower teeth