Bones Notes

Skeletal System

Bones (skeleton)The skeleton has 206 bones

JointsCartilageligaments

Divided into two divisionsAxial 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 bodyProtection of soft organsMovement due to attached skeletal

musclesStorage of minerals and fatsBlood cell formation

(hematopoiesis)

Classification of Bone

Long bonesTypically longer than wideHave a shaft with heads at both

endsExamples: Femur, humerus, radius, ulna, metatarsal, metacarpals

Short bonesGenerally cube-shape

Examples: carpals, tarsals, patella, calcaneus

Flat bonesThin and flattenedUsually curved

Examples: Skull bones (frontal, parietal, temporal, occipital), mandible, ribs, sternum

Irregular bonesIrregular shape or does not fit into

other categoriesExample: Vertebrae and hip

Bone Markings

Surface features of bonesSites of attachments for muscles,

tendons, and ligamentsPassages for nerves and blood

vessels

Categories of bone markings

Projections and processes – grow out from the bone surfaceTuberosity – large round

projectionsTubercle – small, round

projections or processesHead – bony expansion carried

on narrow neck

Trochanter – very large, irregular shaped process

Ramus – armlike bar of boneCondyle – round articular

projectionSpine – sharp, slender, pointed

projection

Crest – narrow ridge of bone’

Depressions or cavities – indentationsMeatus – canal-like passagewaySinus – cavity within a bone filled

with air lined with mucus membrane

Fossa – shallow, basin-like depression

Fissure – narrow slit-like openingForamen – round or oval

opening through bone

Bone Development