Basic functions and structure of skeletal system

6 Basic functions

Support, protection, assist in movement, storage of calcium, blood cell production, storage of chemical energy

Axial skeleton components

skull (facial/cranial), vertebral column (sacrum/coccyx), sternum, ribs

Appendicular skeleton

hands and feet, wrist and ankle, arm and leg, pectoral/pelvic girdle

Long bones

greater length than width, with long shaft (ex. femur, tibula, fibula, humerus, ulna and radius, phalanges)

Short bones

somewhat cube shaped, nearly equal in length and width

Flat bones

generally thin, extensive surface for muscle attachment, provide considerable protection (ex. cranial bones, sternum, ribs, scapulae)

Irregular bones

complex shapes (ex. vertebrae, some facial bones)

Sesamoid bones

protects tendons from wear and tear (ex. patella)

Diaphysis

long, cylindrical, main portion of the bone

Epiphysis

distal and proximal ends of the bone

metaphysis

regions in mature bone where epiphysis meets the diaphysis

in growing bone includes the epiphyseal plate

epiphyseal plate

layer of cartilage that is being replaced by bone; bone grows in length

Articular cartilage

reduces friction/absorbs shock

spongy bone

contains red marrow, found in hip bones, ribs breast bones, vertebrae and the ends of long bones

spaces within the spongy bone is filled with red bone marrow

trabeculae

irregular, criss-crossing of thin columns of bone

compact bone

contains few spaces

external layer of all bones of the body and the bulk of the body of long bones

provides protection, support, resistance to stress

Marrow cavity

space within the diaphysis which contains fatty yellow marrow in adults

Periosteum

tough sheath of dense irregular connective tissue; surrounds the bone surface, protection

assists in fracture repair

helps nourish bone

serves as point of attachment for ligaments/tendons

endosteum

lines the surface of marrow cavity, contains bone forming cells that contribute to growth in width of the bone