Divisions of the Skeleton

Includes skull, spine, and ribs. Axial Skeleton Includes skull, spine, and ribs.

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

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

Color code letters A-L on the skull. Sutures (a,b,c)

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

Frontal Bone Contains 2 sinuses Sinuses ?

Parietal Paired (2)

Occipital

Temporal Bone Paired (2)

Sphenoid (page 139)

Ethmoid Bone

Lines where bones meet, immovable joints. Sutures (a,b,c) Lines where bones meet, immovable joints.

Fontanels Soft spots with no bones when babies are born. (Connective tissue)

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

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

External Auditory Meatus Opening in temporal bone for ear canals.

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

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

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

Lacrimal (2) Thin and scale like.

Two rectangles that fuse and form the bridge of the nose. Nasal Bone (2) Two rectangles that fuse and form the bridge of the nose.

Zygomatic Bone (2) Cheek bones. ‘Zygomatic Arch’ connects to the temporal bone.

Maxilla (2) Form the floor of the nasal cavity and the roof of the oral cavity (hard palate). Upper jaw

Mandible (only movable face bone)

?

OSSICLES Bones in the ears. (Smallest bones in the body) Hammer Anvil Stirrup Mallus Incus Stapes

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

Vertebrae

Textbook Page 143 1. Spinous Process 2. Articular Facet 3. Transverse Process 4. Vertebral foramen 5. Body

Are the individual irregular bones that make up the spinal column Vertebrae (F) Are the individual irregular bones that make up the spinal column

Intervertebral discs (D) Made of tough cartilage

Vertebral Column The spine is broken into 4 sections. 1. Cervical 2. Thoracic 3. Lumbar 4. a.Sacrum b.Coccyx

CERVICAL Total = 7 Location = neck #’s = C1-C7

Location = Thoracic cavity Total = 12 Location = Thoracic cavity #’s = T1-T12

LUMBAR VERTEBRAE Total = 5 Location = Lower back #’s = L1-L5

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

Coccyx OUCH!!!!! Tail Bone

Sternum Breast Bone, 3 parts

Manubrium (top) Body (middle) Xiphoid process

RIBS – 12 pairs

True- top 7 pairs, attach directly to sternum False- next 5 pairs, do not attach directly to sternum Floating- bottom 2 ribs, no connection with sternum