Chapter 11

Cranium Part 1

Cranial Bones

• Skull = __________ and ________ bones • Cranium (8 bones) – Area that surrounds and protects the brain.

– ____________ (Skull Cap) – Floor

• __________

Calvarium

• Parietal (Right and Left) • __________

Frontal Bone

• ____________ (Vertical) Portion – Forehead • ___________ (Horizontal) Portion – Superior Orbits

Frontal Bone Squamous •

___________

– Area between eyebrows •

_____________ Groove

– Depression above eyebrows •

______________margin

– Superior rim of orbit •

_____________ ridge (Arch)

– Ridge beneath eyebrow

Frontal Bone Orbital •

_____________plate

– Superior portion of each orbit •

_______________ Notch

– Separates orbital plate • Articulates with 4 cranial bones – Right and left parietals, sphenoid, _________

Parietal Bones

• Forms the __________calvarium.

• Articulates with 5 cranial bones – Frontal, occipital, temporal, sphenoid, parietal

Occipital Bone

• ___________portion of the calvarium.

• Squamous Portion • _______________Protuberance (Inion) – Prominent bump on the back of head.

Occipital

•

____________Magnum

– Hole for spinal cord •

_______________ condyles

– Articulating surface on each side of foramen magnum. • Articulates with 6 bones – 2 parietals, 2 temporals, sphenoid, ________

Cranial Floor

• Temporal (Right and Left) • __________ • Ethmoid

Temporal Bone

• Lateral aspect of skull.

• 3 Portions – ___________ – ___________ – ___________

Temporal Squamous Portion • Vertical aspect and very thin. •

_______________

– Articulates with Zygoma – ____________

Temporal Mastoid Portion • Posterior to ___________ • _____________ • Mastoid Tip

Temporal Petrous Portion • Houses hearing and equilibrium •

_______________

– Petrous Ridges •

_______________Meatus

– Opening for the nerves of hearing and equilibrium •

________________

Sphenoid • Centrally located. Anchors all 7 cranial bones.

•

_______________

(Turk’s Saddle) – Houses _______________ – __________sellae – Posterior wall of sella – _____ – Depression posterior to dorsum sella. – Posterior clinoid – Anterior clinoid

Sphenoid

•

___________ Wings

– Anterior clinoid •

___________ Wings

– Forms portion of floor and walls of cranium

Sphenoid

•

Lateral ______________

– Lateral downward projections •

Medial ________________

– Medial downward projections •

___________ hamuli

– Process off of medial pterygoid

Sphenoid Foramen

• Foramen ____________ • Foramen ____________ • Foramen ____________

Sphenoid Optic Components •

Optic __________ (Chiasm)

– Groove between Anterior body and lesser wings •

Optic ___________

– Hole between anterior body and lesser wings •

Superior ______________

– Space lateral to optic foramen between lesser and greater wings

Ethmoid Bone

• Small bone lying primarily below floor of cranium. • Articulates with 2 cranial bones. •

____________

– Horizontal portion •

____________

– Superior projection from cribriform plate into frontal bone

More Ethmoid

•

_________________ plate

– Downward projection forms nasal septum •

Lateral _____________ (masses)

– Suspend from cribiform •

Nasal ___________(Turbinates)

– Downward projection from labyrinth

Sutures

• • • • • Areas of cranial fusion – Synarthrodial

__________ suture

– Fuses Parietal to Frontal bone

___________suture

– Fuses right and left Parietal

__________suture

– Fuses Parietal to Occipital

__________ suture

– Fuses Parietal to Temporal

Fontanels

Membrane area as a Child • Anterior • Posterior • Sphenoid (2) • Mastoid (2)

Suture Articulations Adult

• • • •

____________

– Frontal and parietals

____________

– Occipital and parietals

___________ Rt/Lt

– GW of sphenoid, temporal, parietal, frontal

___________ Rt/Lt

– Temporal, occipital, parietal