Divisions of the Skeleton

Divisions of Divisions of the Skeletonthe Skeleton

Axial SkeletonAxial Skeleton

Includes skull, Includes skull, spine, and ribs.spine, and ribs.

SkullSkull

Made up of 22 Made up of 22 Bones:Bones:Facial bones = 14Facial bones = 14Cranium =8Cranium =8

CRANIUMCRANIUM

Bones that Bones that enclose enclose the brain the brain (8).(8).

COLOR CODECOLOR CODE

Color code letters A-L Color code letters A-L on the skull.on the skull.

Sutures (a,b,c)Sutures (a,b,c)

A. Frontal boneA. Frontal bone B. Pariatal bone (paired)B. Pariatal bone (paired) C. Occipital boneC. Occipital bone D. Temporal bone (paired)D. Temporal bone (paired) E. Sphenoid (connects cranium to facial)E. Sphenoid (connects cranium to facial) F. Ethmoid (roof and sides of the nasal F. Ethmoid (roof and sides of the nasal

passage)passage)

Frontal BoneFrontal Bone

Contains 2 Contains 2 sinusessinuses

Sinuses ?Sinuses ?

ParietalParietal

Paired (2)Paired (2)

Occipital Occipital

Temporal BoneTemporal Bone

Paired (2)Paired (2)

Sphenoid (page 139)Sphenoid (page 139)

Ethmoid BoneEthmoid Bone

Sutures (a,b,c)Sutures (a,b,c)

Lines where Lines where bones meet, bones meet, immovableimmovable joints.joints.

FontanelsFontanels Soft spots with no bones when Soft spots with no bones when

babies are born. (Connective babies are born. (Connective tissue)tissue)

FontanelsFontanels

As a fetus develops, its brain grows As a fetus develops, its brain grows rapidly. The skull is growing as well but rapidly. The skull is growing as well but can not keep up. Fusion of the bones can not keep up. Fusion of the bones begins, but will complete after birth. A begins, but will complete after birth. A new born generally has 2 frontal bones, 4 new born generally has 2 frontal bones, 4 occipital bones, and several sphenoid occipital bones, and several sphenoid and temporal bones. These bones are and temporal bones. These bones are held together by fontanels. held together by fontanels.

Foramen MagnumForamen Magnum

Opening in Opening in occipital occipital bone for bone for spinal cord spinal cord exit.exit.

External Auditory MeatusExternal Auditory Meatus

Opening in Opening in temporal temporal bone for bone for ear canals.ear canals.

Styloid ProcessStyloid Process

Sharp bone Sharp bone projection to projection to help anchor help anchor muscles muscles assoc. with assoc. with the tongue.the tongue.

FacialFacial

Bones NOT Bones NOT enclosing brains enclosing brains (13 immovable + 1 (13 immovable + 1 movable = 14).movable = 14).

Facial bonesFacial bones

G. Lacrimal (2)G. Lacrimal (2) H. Nasal Bone (2)H. Nasal Bone (2) I. Zygomatic (2) Cheek bonesI. Zygomatic (2) Cheek bones J. Maxilla (2) upper jawJ. Maxilla (2) upper jaw K. Mandible *Only movable joint in K. Mandible *Only movable joint in

the skull.the skull.

Lacrimal (2)Lacrimal (2)

Thin and scale Thin and scale like.like.

Nasal Bone (2)Nasal Bone (2)

Two Two rectangles rectangles that fuse and that fuse and form the form the bridge of the bridge of the nose.nose.

Zygomatic Bone (2)Zygomatic Bone (2)

Cheek bones.Cheek bones. ‘‘Zygomatic Zygomatic

Arch’ connects Arch’ connects to the temporal to the temporal bone.bone.

Maxilla (2) Maxilla (2)

Form the floor Form the floor of the nasal of the nasal cavity and the cavity and the roof of the oral roof of the oral cavity (hard cavity (hard palate).palate).

Upper jawUpper jaw

Mandible (only movable Mandible (only movable face bone)face bone)

??

OSSICLESOSSICLES

Bones in the ears. Bones in the ears. (Smallest bones in (Smallest bones in the body)the body)

Hammer Anvil StirrupHammer Anvil StirrupMallusMallus Incus Stapes Incus Stapes

HyoidHyoid

Attachment for Attachment for movement of movement of the tongue, the tongue, doesn’t touch doesn’t touch any other any other bones-base of bones-base of the tonguethe tongue

VertebraeVertebrae

Textbook Page 143Textbook Page 143

1. Spinous Process1. Spinous Process 2. Articular Facet2. Articular Facet 3. Transverse 3. Transverse

ProcessProcess 4. Vertebral foramen4. Vertebral foramen 5. Body5. Body

Vertebrae (F)Vertebrae (F)

Are the Are the individual individual irregular boneirregular boness that make up that make up the the spinal columnspinal column

Intervertebral discs (D)Intervertebral discs (D)

Made of Made of tough tough cartilagecartilage

Vertebral ColumnVertebral Column The spine is broken The spine is broken

into 4 sections.into 4 sections. 1. Cervical1. Cervical 2. Thoracic2. Thoracic 3. Lumbar3. Lumbar 4. a.Sacrum4. a.Sacrum b.Coccyxb.Coccyx

CERVICAL CERVICAL

Total = 7Total = 7Location = Location =

neckneck#’s = C1-C7#’s = C1-C7

ThoracicThoracic

Total = 12Total = 12Location = Location =

Thoracic Thoracic cavitycavity

#’s = T1-T12#’s = T1-T12

LUMBAR VERTEBRAELUMBAR VERTEBRAE

Total = 5Total = 5 Location = Location =

Lower backLower back #’s = L1-L5#’s = L1-L5

SacrumSacrum

5 fused 5 fused sacral sacral discs at discs at base of base of spine.spine.

CoccyxCoccyx

Tail Tail BoneBone

OUCH!!!!!

SternumSternumBreast Breast Bone, 3 Bone, 3 partsparts

Manubrium (top)Manubrium (top)Body (middle)Body (middle)Xiphoid processXiphoid process

RIBS – 12 pairsRIBS – 12 pairs

True- top 7 pairs, attach directly to True- top 7 pairs, attach directly to sternumsternum

False- next 5 pairs, do not attach False- next 5 pairs, do not attach directly to sternumdirectly to sternum

Floating- bottom 2 ribs, no Floating- bottom 2 ribs, no connection with sternum connection with sternum