4 Types of Bones&

Skeletal Organization

ACOS OBJ 6.4)identifying the four bone types. 6) Identify bones that compose the skeletal system. 6.2) identifying subdivisions of the skeleton as axial & appendicular skeletons.

4 Types of Bones

• 1. Long Bones: Hard dense bones that consist of a shaft & two ends. Composed mostly of compact bone.– EX: Femur, Humerus, Tibia

2. Short Bones: length and width are the close to the same. Composed mostly of spongy bone.

(cube-shaped)-EX: Carpals(wrist bones), and tarsals(ankle bones)

3. Flat Bones: relatively thin and FLAT. -EX: sternum, ribs, scapula, and Cranial bones

4. Irregular Bones: Odd shaped bones -EX: Facial Skeleton, Vertebrae, and Sacrum

•

Examples of Long Bones

Examples of Short Bones

Examples of Flat Bones

Examples of Irregular Bones

Skeletal Organization• There are 2 major portions of the skeletal system.

– 1. Axial Skeleton (Ax-?): Bony & cartilaginous parts that support & protect organs of the head neck and trunk.

– 2. Appendicular Skeleton: Bones of the upper & lower limbs

–Bones that anchor limbs to the axial skeleton

Axial Skeleton• 1. Skull

– Composed of the cranium & facial bones.

2. Hyoid Bone- located in the neck between the lower jaw & larynx.- Supports the tongue & is an attachment for certain muscles that help move the tongue during swallowing.

3. Vertebral Column ( Backbone) – Many vertebrae separated by intervertebral discs.

-Distal end several vertebrae fuse together to form the SACRUM

- Coccyx: Located at the end of the sacrum.

Axial Skeleton Continued• 4. Thoracic Cage: Protects organs of thoracic cavity &

the upper abdominal cavity.– 12 Pairs of Ribs ( Articulate posteriorly w/ thoracic

vertebrae & anteriorly w/ the sternum.

Axial Skeleton

Appendicular Skeleton• 1. Pectoral Girdle

– Composed of the SCAPULA & CLAVICLE- connects the bones of upper limbs to the axial skeleton

Appendicular Skeleton Continued

• 2. Upper Limbs– Consist of:

• 1 humerus• 2 forearm bones ( Radius & Ulna)• A Wrist ( 8 carpals)• A Hand ( 14 Phalanges)• 5 Metacarpals in the palm

-Radius - Ulna- Humerus→ Articulate w/ each other at

- The elbow joint

Distal Upper Limb

• 3. Pelvic Girdle– 2 Coxae ( hipbones)

• Connects bones of lower limbs to the axial skeleton- Sacrum- Coccyx

• 4. Lower Limbs– Femur ( Thighbone)– 2 leg bones ( Large TIBIA & slender FIBULA )– Ankle ( 7 Tarsals) Distil end of Tibia & Fibula– 5 Metatarsals– 14 phalanges

Lower Limbs

Pg.137 Table 7.2