Divisions of the Skeleton Axial Skeleton Includes skull

Divisions of the Skeleton

Axial Skeleton §Includes skull, spine, and ribs.

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

CRANIUM § Bones that enclose the brain (8).

COLOR CODE § 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

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.

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

External Auditory Meatus § Opening in temporal bone for ear canals.

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

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.

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

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 = C 1 -C 7

Thoracic § Total = 12 § Location = Thoracic cavity § #’s = T 1 -T 12

LUMBAR VERTEBRAE § Total = 5 § Location = Lower back § #’s = L 1 -L 5

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