Osteology

functions of bones

support, protection, movement, storage, blood cell formation

axial skeleton

head and trunk

appendicular skeleton

limbs, pelvic bones

long bones

longer than they are wide (femur, humerus, metacarpals)

short bones

approximately cubed in shape (carpals, tarsals)

flat bones

thin, flattened plates (sternum, ribs, some skull bones)

irregular bones

complicated shaped (vertebrae, hip bones)

sesamoid bones

embedded with a tendon (patella)

compact bone

forms a dense outer wall of bones, comprised of functional units called osteons

spongy bone

found internal to compact bone in most places, forms mesh-like network of bony spicules called trabeculae, spaces between are filled with bone marrow

epiphysis

end of the long bone, composed of compact bone on the outside and spongey bone on the inside

diaphysis

shaft of long bone, composed of compact bone and medullary/marrow cavity

epiphyseal plate/line

between diaphysis and epiphysis, in growing individuals composed of hyaline cartilage, in adults bone tissue

articular cartilage

hyaline cartilage that covers the joint surface of the epiphysis

medullary cavity (marrow cavity)

rilled with red bone marrow (site of hematopoiesis) or yellow bone marrow (stores triglycerides for energy)

periosteum

external double layer of connective tissue, attachment site for muscle tendons

endosteum

internal layer of connective tissue, lines medullary cavity, covers trabeculae of spongy bone

Compact bone histology

spongey bone histology

osteoblasts

build new bone

osteoclasts

consume bone

osteoctyes

maintain bone