SkeletonDivided into sections

Axial

Appendicular

Made of 206 bones

Provides a framework that supports and protects organs in the dorsal and ventral body cavitiesJoints are rigid and have limited movement but are very strongMade of 80 bones

Skull and Associated Bones

Occipital bone (1)

Parietal Bones (2)

Frontal Bone

Temporal Bone (2)

Sphenoid Bone

Ethmoid bone

Skull and Associated BonesProtect and guards entrance to the digestive and respiratory tractCranial bones- enclose the cranial cavity, a fluid filled chamber that cushions and supports the brain

Inner surface has blood vessels, nerves, and membranes that stabilize the brainOuter surface provides area for attachment of muscle that move eyes, jaws, and head

Sutures of the skull

Connections between the skull bones are immovable joints called sutures (connection of mandible is an exception)

Skull SuturesLamboidal suture- arches across the posterior surface of the skull. Separates the occipital bone from the parietal bones.

Coronal Suture- arches across the top of the skull. Separates the frontal bone from the parietal bones.

Sutures cont.Sagittal Suture- goes between the lamboidal and coronal sutures splitting the 2 parietal bones

Squamous Sutures (2) - one on each side of the head between the parietal and temporal bones

Facial Bones (14)Maxillary bones

Palatine bones

Nasal bones

Vomer (1)

Inferior nasal conchae

Zygomatic bones

Lacrimal bones

Mandible (1)

Infant SkullBone growth is attempting to keep up with brain development, so at birth bones haven’t fused together yet

At approx. age 5 brain stops growing so does the skull, and the cranial sutures develop

FontanelsFontanel- large fibrous areas between skull bones

Anterior, Occipital, Sphenoidal, and Mastoid Fontanels

Occipital, sphenoidal, and mastoid fontanels disappear 1-2 months after birth, and the anterior fontanel persists until age 2