2 Divisions Cranium Face THE SKULL 2 Divisions Cranium Face

Most complex bony structure 22 bones in all Mostly flat bones, but not all!

Cranial Bones: 8 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 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