THE SKULL
2 Divisions
Cranium
Face
• Most complex bony structure
• 22 bones in all
• Mostly flat bones, but not all!
Cranial Bones: 8
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Friday Find and describe:
1. frontal bone
2. occipital bone
3. sphenoid bone
4. ethmoid bone
5. parietal bones (2)
6. temporal bones (2)
Functions of Cranial Bones
• Enclose and protect the brain
• Attachment sites for head and neck
muscles
Functions of Facial Bones
• 1. form framework of face
• 2. contain cavities for special sense
organs
• 3. openings for food/air passage
• 4. secure the teeth
• 5. anchor the facial muscles of expression
• ALL BONES OF THE SKULL ARE
FIRMLY LOCKED IN PLACE BY JOINTS
CALLED SUTURES
• Four major sutures
THE CRANIUM (8)
1 frontal bone
2 parietal bones
2 temporal bones
1 occipital bone
1 sphenoid bone
1 ethmoid bone
THE FRONTAL BONE
Parietal Bones: Form most of the superior and
lateral aspects of the skull
Figure 7.3a
Parietal Bones
• Curved, rectangular bones forming
majority of the cranium
• All four major sutures articulate with this
bone
Look up the 4 major sutures of
the skull
Parietal Bones and Major Associated Sutures
• Four sutures mark the articulations of the
parietal bones
– Coronal suture – articulation between
parietal bones and frontal bone anteriorly
– Sagittal suture – where right and left parietal
bones meet superiorly
– Lambdoid suture – where parietal bones
meet the occipital bone posteriorly
– Squamosal or squamous suture – where
parietal and temporal bones meet
Occipital Bone and Its Major
Markings
• Forms most of
skull’s posterior
wall and base
• Major markings
include the
posterior cranial
fossa, foramen
magnum, occipital
condyles, and the
hypoglossal canal
Figure 7.2b
Temporal Bones
• Lateral sides of the skull
• Zygomatic process connects with
zygomatic arch
• External auditory meatus (external ear)
• Styloid process muscle attachment for
tongue and neck
• Mastoid process neck muscles
Temporal Bones
Figure 7.5
Sphenoid Bone
• Spans width of middle cranial fossa
• Articulates with all other cranial bones
• Three parts greater wing, lesser wing
and pterygoid processes
• Sella turcica enclosure for pituitary
gland
Ethmoid Bone
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Complex shape
Nasal cavity and orbital cavity
Cribriform plate roof of the nasal cavity
Crista galli- outermost covering of the
brain cover connects here
Maxillary Bones
• Medially fused bones that make up the
upper jaw and the central portion of the
facial skeleton
• Facial keystone bones that articulate with
all other facial bones except the mandible
• Their major markings include palatine,
frontal, and zygomatic processes, the
alveolar margins, inferior orbital fissure,
and the maxillary sinuses
Maxillary Bone
Figure 7.8b