Bones Notes

Skeletal System Bones (skeleton) The skeleton has 206 bones Joints Cartilage ligaments

Divided into two divisions Axial skeleton – bones of face & skull, vertebrae, sternum, ribs, sacrum Appendicular skeleton – bones of pectoral & pelvic girdle, extremities (arms & legs), bones of hands and feet

FUNCTION Support of the body Protection of soft organs Movement due to attached skeletal muscles Storage of minerals and fats Blood cell formation (hematopoiesis)

Classification of Bone Long bones Typically longer than wide Have a shaft with heads at both ends Examples: Femur, humerus, radius, ulna, metatarsal, metacarpals

Short bones Generally cube-shape Examples: carpals, tarsals, patella, calcaneus

Flat bones Thin and flattened Usually curved Examples: Skull bones (frontal, parietal, temporal, occipital), mandible, ribs, sternum

Irregular bones Irregular shape or does not fit into other categories Example: Vertebrae and hip

Bone Markings Surface features of bones Sites of attachments for muscles, tendons, and ligaments Passages for nerves and blood vessels

Categories of bone markings Projections and processes – grow out from the bone surface Tuberosity – large round projections Tubercle – small, round projections or processes Head – bony expansion carried on narrow neck

Trochanter – very large, irregular shaped process Ramus – armlike bar of bone Condyle – round articular projection Spine – sharp, slender, pointed projection

Crest – narrow ridge of bone’

Depressions or cavities – indentations Meatus – canal-like passageway Sinus – cavity within a bone filled with air lined with mucus membrane

Fossa – shallow, basin-like depression Fissure – narrow slit-like opening Foramen – round or oval opening through bone

Bone Development