STRUCTURE OF A LONG BONE

GROSS ANATOMY DIAPHYSIS – shaft DIAPHYSIS – shaft Makes up most of bone’s length Makes up most of bone’s length Composed of compact bone Composed of compact bone

Periosteum Fibrous connective tissue membrane Fibrous connective tissue membrane Covers and protects diaphysis Covers and protects diaphysis Connected by Sharpey’s Fibers Connected by Sharpey’s Fibers

EPIPHYSES Ends of long bone Ends of long bone Composed of thin layer of compact bone enclosing area of spongy bone Composed of thin layer of compact bone enclosing area of spongy bone

ARTICULAR CARTILAGE Covers epiphyses Covers epiphyses Glassy, hyaline Glassy, hyaline Provides smooth, slippery surface to decrease friction at joints Provides smooth, slippery surface to decrease friction at joints

Epiphyseal Line Adult bones: thin line of bony tissue spanning the epiphysis Adult bones: thin line of bony tissue spanning the epiphysis Remnant of epiphyseal plate (plate of hyaline cartilage in young, growing bone) Remnant of epiphyseal plate (plate of hyaline cartilage in young, growing bone) Cause lengthwise growth until end of puberty Cause lengthwise growth until end of puberty

MEDULLARY CAVITY Yellow marrow – cavity of shaft Yellow marrow – cavity of shaft In adults: storage for adipose tissue In adults: storage for adipose tissue In infants: area forms blood cells, red marrow In infants: area forms blood cells, red marrow (In adults: red marrow is confined to cavities of spongy bone of flat bones, and epiphyses of some long bones: sternum, ribs, femur, cranium) (In adults: red marrow is confined to cavities of spongy bone of flat bones, and epiphyses of some long bones: sternum, ribs, femur, cranium)